One element of being scientifically literate is the ability to identify the actual conclusion(s) of a given scientific paper. Here's what the Harvard study actually says (from the link in the OP):
"The results suggest that fluoride
may be a developmental neurotoxicant that affects brain development at exposures much below those that can cause toxicity in adults"
"In conclusion, our results support
the possibility of adverse effects of fluoride exposures on children's neurodevelopment."
Now, identifying the author's conclusion is not necessarily the same thing as identifying the true implications of a given study; an author may draw incorrect deductions from the research. But, absent scientific argument to the contrary, in this instance it makes sense to suppose the authors of the study assessed the evidence properly.
Here are the author's feelings -- contra scientifically illiterate, weed-abusing conspiracy theorists -- regarding the applicability of their research to American citizens:
“These results do not allow us to make
any judgment regarding possible levels of risk at levels of exposure typical for water fluoridation in the U.S.,” say two of the researchers in an email signed off by the two primary authors of the study.
http://www.kansas.com/2012/09/11/2485561/harvard-scientists-data-on-fluoride.htmlThey say this because 25 of the 27 studies analyzed were undertaken in rural China, where fluoride consumption is at times 10 times as high as any U.S. city. Also, the Harvard researchers did not gather any of the data themselves since it was a meta-analysis; unless I'm mistaken, that means the inherent limitations of the individual studies -- not controlling for socioeconomic status and other essential variables -- necessarily affect the veracity of the meta-analysis in a way not correctable by its researchers.
The Harvard researchers' primary conclusion is that further research is needed. I think everybody can agree to that. Let's not be irrational and jump to vast conclusions far and above those supported by the data -- as tempting as it is for some. (Perhaps fluoride is negatively impacting children in the U.S., and perhaps this fact will be conclusively supported by the data. That's the time to be angry about it, when the actual data definitively supports the claim. It would be fallacious for those crying about it now to say, "I told you so," since they were telling us so on the basis of insufficient evidence.)
