Thank you for your interest in my initial post.
By my lights, there are two issues.
The first issue is (for lack of a better word) "intuitive." To be more exact, the question, here, is what pre-reflective, pre-investigative position does a given individual take with respect to "water fluoridation"? This is not a matter of "feeling," but a matter of honestly assessing one's tentative starting point.
Ignoring irrational and dogmatic opinions, roughly sketched, the reasonable "options" might be:
(1) antecedent skepticism (that is, being conditionally "against" fluoridation);
(2) antecedent trust (i.e., being caautiously "for" it; or
(3) antecedent agnosticism (where I mean "agnosticism" to designate a sort of provisional "neutrality")
Briefly, I think that antecedent skepticism could be rational in cases where persons begin from positions with some combination of the following features: awareness of the history of the eugenics movement in the U.S. ; awareness of the historic use of sodium fluoride as an insecticide ; awareness of the history in the U.S. of periodic chemical agent and medical "testing" on unsuspecting (and therefore nonconsenting) persons ; and other factors in the vicinity. 
Although, I hasten to add that I think much less "exotic" considerations could be determinative. For instance, I think it altogether appropriate to doubt the wisdom of introducing into something as necessary for human life as clean drinking water a compound that, as you put it, "can absolutely hurt (and kill)" a person in such-and-so concentration. The precise harmful or lethal concentration will almost certainly vary from person-to-person, according to such "confounding factors" as genetic proclivity, immune functionality, chemical-cofactors, and much else besides. Thus, remarks to the effect that damaging results should be expected from "levels ...far, far above what we consume" are little more than hand waving (if not wishful thinking).
Frankly, I confess myself an antecedent skeptic. I concede, however, that some persons could rationally profess antecedent agnosticism, or even antecedent trust. These could occur in cases where persons are unaware of the background information that supports antecedent skepticism, or where persons hold beliefs such as: the idea that such a scenario is unreasonably ascribed to nefarious intentionality ; the notion that consumption of sodium fluoride has been "demonstrated" to be innocuous or even "helpful"; and so forth.
This last consideration leads directly to the second issue.
Here we are not concerned with the (highly belief-relative and variable) psychological dispositions of untutored people in a given population, but with the conclusions and opinions of those persons who are, by some measure or other, assigned the label "scientific experts" in the relevant area.
Admittedly, with respect to this issue I - and I presume you, too - can merely gesture towards particular scientific papers.
However, there are two subsidiary issues that arise immediately, one about the philosophy of science, the other about human psychology.
Number one, with the possible exceptions of (certain branches of) logic and mathematics, the epistemic standard of judgment in all areas of human inquiry must be a assessed in terms of the caliber of one's evidence. To be more precise, words like "proof" ("proved," and related cognates), "disproof," "refute," etc. have no application in science. One speaks instead of "corroboration," "dis-corroboration," and so on; and, in some jargon "dialects," "confirmation," "disconfirmation," and related terms.
This is an important consideration, here, since some - perhaps untrained in the philosophy of science - might think that a follow-up study on some topic automatically "supersedes" or "puts to rest" issues raised in previous studies. This is not the case.
That "your" study's "findings do not support the assertion that fluoride in the context of CWF programs is neurotoxic" is certainly not definitive.
Let's not confuse ourselves. It's interesting. It's important. It raises questions like, if fluoride was linked to lower IQs by investigators at the school of public health at Harvard University, why didn't the dental researchers at the University of Otago in New Zealand find the same thing? 
However, to echo the words of the article abstract to which you linked, there may be any number of "potential confounding variables" such as water-additive co-factors, methodological variables , definitional variables, etc.; any or all of which might explain the discrepancy between the two studies without resorting to the conclusion that the Harvard study is (either wholly or even partially) incorrect.
I note two concrete examples of such possible variation.
In the first place, the study that you cite says that it was concerned with "fluoride dentifrice and intake of 0.5-milligram fluoride tablets".
In my area of St. Charles County, the "Optimal fluoride concentration" is given at "1.00 mg/L". <http://apps.nccd.cdc.gov/MWF/CountyDataV.asp%3FState=MO>. The same number is given for Oak Park. <http://apps.nccd.cdc.gov/MWF/CountyDataV.asp%3FState=IL>.
Because you did not link to an entire article, as I did, but only an abstract, it is not possible for me to compare these numbers further. Depending on the amount of water in question, it might be - for all the information we have presently available - that the New Zealand study was concerned with ingested fluoride at half the level of what people in our two counties are exposed to.
In the second place, it might be - again, for all that is available to inspect in the abtract - that the two studies were operating on subtly (or not-so-subtly) divergent definitions of (or standards for measuring) key things such as "neurotoxicity."
Number two, it is simply a predictable matter of psychology that people will gravitate towards findings that tend to "confirm" their presuppositions. This is likely as true for my posting of the initial Harvard article as it is for your post of the allegedly disconfirming Otago abstract.
Since neither of us (I'd wager) is planning on acquiring a degree in chemistry or health or biology - or any other "hard" scientific field possibly relevant to the experimental side of the question of the safety of water fluoridation, I put it to you that we must fall back upon other resources when faced with the prospect of coming to some conclusions.
There is a epistemological considerations known as "methodological conservatism" that is relevant, here (in my opinion). According to methodological conservatism, "we are entitled to maintain beliefs we already have, all other things being equal." 
When I consider the point (already articulated, supra.) about the dialectical (and inconclusive) nature of scientific inquiry, in conjunction with my very expansive set of background information (regarding widespread medical and pharmaceutical malfeasance in the country, infra.) - even apart from ancillary factors like the relative university ratings - I must conclude (tentatively, as always) that there is very little reason for me to alter my beliefs in virtue of your citation of an *abstract* asserting conclusions to the contrary.
From a theoretical standpoint, the Otago study abstract, while provocative, is neither (nor could it be) definitive (given the nature of scientific inquiry), nor even persuasive to me (since, for one thing, I cannot even read the entire article). For me, given my background assumptions, the higher credibility of the Harvard study as compared with the (heretofore unknown to me) Otago University, compels me to say that skepticism of water fluoridation (if not outright opposition to it) is, on balance, the far more compelling position.
From a practical standpoint (and whatever else it may be, drinking water is surely a very practical affair), the simple fact is that I would rather drink filtered water and risk tooth decay than drink fluoridated water and risk mental impairment.
Therefore, I believe that the wisest practical step for me and my family would be for me to invest in a water filter and use it. While we are enjoying pure, nutrifying hydration, the scientists can battle it out over fluoride in their respective journals.
~ Matthew J. Bell
Sept. 2, 2014
 See, e.g., http://www.cbsnews.com/news/americas-deep-dark-secret/; http://ideas.time.com/2013/07/10/eugenics-are-alive-and-well-in-the-united-states/
 To give just one example of this, I quote from Patent No. 5,935,943: "Traditionally, the active ingredient used for exterminating harmful wood eating insects ...has been an inorganic compound (such as ...sodium fluoride...) ...These compounds are frequently used because of their excellent stability and residual effect in wood and their low cost. However, these compounds are highly toxic... They are also very persistent in the human and animal body, and so, once they have entered the food chain, for example in the fat in fish or shellfish, they remain in the ecosystem, where their presence has become a problem. The manufacture, sale, import, and the like of these compounds are restricted in many countries, and most of them are prohibited from being used." <http://www.patentbuddy.com/Patent/5935943>.
 The most infamous case, surely, is the Tuskegee syphilis incident. The opening paragraph of Wiki's article reads: "The Tuskegee syphilis experiment ...was an infamous clinical study conducted between 1932 and 1972 by the U.S. Public Health Service to study the natural progression of untreated syphilis in rural African American men **who thought they were receiving free health care from the U.S. government**." <http://en.wikipedia.org/wiki/Tuskegee_syphilis_experiment>
Put roughly, an antecedent fluoridation skeptic might worry that, at some future time, a similar article might read: "The water fluoridation experiment ...was an infamous clinical study conducted between 1950 (or so - I'm winging it) and 20XX by [persons now unknown] to study the intelligence-reducing effects of sodium fluoride ingesiton across a broad cross-section of the American population who thought that they were reducing their susceptibility to tooth decay."
Of course, this is merely an illustration - not an argument. Nevertheless, the Tuskegee event shows unambiguously that humans are, firstly, not above violating the autonomy of their fellow beings by conducting immoral and illegal "experiments" on them; and, secondly, that such activities can proceed apace for decades.
For other examples of such things, see a previous blog post of mine, here: <http://curveofbell.blogspot.com/2012/12/media-mistakes-as-digital-dye.html>.
 One might also cite the conjunction of vaccines with sterilizing agents (or "immunizations" against pregnancy), references concerning with can be found in Catherine Diodati's book Immunization: History, Ethics, Law, and Health (Windsor, Ont.: Integral Aspects, 1999).
 And where such persons are unaware of cases - most prominently the Manhattan Project - which involved massive amounts of material resources, money, and man-power and yet were kept secret (by most reasonable - and certainly be official military, standards).
 In passing, I note that Harvard University, the institution that produced the study to which I linked, was in 2013 ranked the #2 university in the world, and #1 in the world in terms of academic reputation. See <http://www.topuniversities.com/node/2547/ranking-details/world-university-rankings/2013>.
By contrast, during the same year, the University of Otago was ranked 155 in the world and 164 in the world in terms of academic reputation. <http://www.topuniversities.com/node/4417/ranking-details/world-university-rankings/2013>.
I have put this in an end note in order not to lay upon it undue emphasis.
 Jonathan Vogel, "Can Skepticism Be Refuted? The Refutation of Skepticism," Contemporary Debates in Epistemology, Oxford: Blackwell, 2005, p. 74.