Yeah, I know at least 4 of my ancestors should have been diagnosed as Autistic but never got tested. And 2 more were for sure undiagnosed ADHD. They all just ended up being stunted unhappy people instead that had a couple happy moments with their other stunted unhappy friends whenever they would hang out and play trains or music or whatever other “weirdly” deep hobby their sposes had to eventually pull them away from to go back to “normal” life.
That paper specifically concludes that despite all that, there is no reason to even look into whether fluoridation in drinking water might be a problem because there has clearly been no corollary deleterious effect. So, knowing what it would look like if it was a problem, was enough to know that it isn’t even close enough to warrant checking how close it is. The highest reported extremes of exposure already didn’t cause issue, so there is certainly no cause for concern at normal levels.