We have a natural experiment running for 80 years where each arm of the experiment has N > 100e6. If there was going to be evidence of community water fluoridation lowering IQ, it would have emerged by now.
They found drinking water with levels that lowered IQ. The actual conclusion was that higher levels (that were found in drinking water) lower IQ.
For lower levels the conclusion is we don't know how it effects IQ. The actual bold face conclusion is "More research is needed to better understand if there are health risks associated with low fluoride exposures".
in 2020: https://www.ncbi.nlm.nih.gov/books/NBK555056/
and again in 2021: https://nap.nationalacademies.org/read/26030/chapter/1
Why was this substandard draft even published?!
It seems that this team found what they wanted to find. Are they scientists or ideologues? Were they creating the 'evidence' for the San Francisco trail?