That isn't what the article says. It isn't even evaluation of other people's research, let alone novel research in itself. It's a "perspective" article commenting on human behavior.
Meanwhile researchers who have conducted proper meta-analyses of the literature have come to a negative conclusion on this topic:
In conclusion, based on the totality of currently available scientific evidence, the present review does not support the presumption that fluoride should be assessed as a human developmental neurotoxicant at the current exposure levels in Europe.
There have been a lot of studies done, dose-response studies too. It gets ignored in the US because of left-right polarization. Here are a few below. Believe what you want I guess but this is basically overwhelming evidence to me.
Thanks, and you can believe what you want as well.
That said, let's note please that these are all associational, rather than cause-and-effect findings. The matter should definitely be explored further - but in my book I would need significant evidence of a causative relationship to check the "overwhelming evidence" box.
Meanwhile researchers who have conducted proper meta-analyses of the literature have come to a negative conclusion on this topic:
In conclusion, based on the totality of currently available scientific evidence, the present review does not support the presumption that fluoride should be assessed as a human developmental neurotoxicant at the current exposure levels in Europe.
https://pubmed.ncbi.nlm.nih.gov/32382957/