You want some fancy rebuttal to a single linked study that the article states was a bunch of partials thrown together, that came from a country famously known for half-assing and cutting corners to get ahead? The country that was caught mixing lead into ground Cinnamon to sell it for a higher weight? The one where buildings sit half done or the cement falls apart by the time it's together? The ones who lay sod over cement in order to pass the amount of vegetation present on new construction?

That's the article you could and and latch onto in order to believe? Are you even aware that fluoride occurs naturally in water and that about 40% of all the drinking water across the globe already has around the amount the US gets theirs up to, or a larger amount(some places so large they do actually cause health issues)? It's literally been drank for thousands of years.

But you trust an incomplete study from China more than anything else? Why?

There’s a follow up meta study from 2020.:

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.

A study in Canada was published in 2019 looking at the differences between 2 neighboring cities where on stopped fluoridating water in 2011. They saw that saw a significant increase in cavities in children in the city that stopped fluoridating vs the other. This is despite the fact the the city without fluoridation actually has somewhat higher adherence to brushing, flossing, and going to the dentist. No difference was seen yet in permanent teeth, but that's because the study would need more time to see effects there.

https://onlinelibrary.wiley.com/doi/full/10.1111/cdoe.12685

Of course, we still should do more studies on fluoride neurotoxicity. Most studies look at levels of fluoride at 1.5mg/L or higher, which is more than double the recommended level by the US (0.7 mg/L). There is a hard limit in the US of 4mg/L, but the EPA strongly recommends a limit of 2mg/L. This only really matters for locations with very high levels of fluoride in the groundwater, and is thus quite rare. The EU's limit is 1.5mg/L.

I also came across the same study while looking to disprove a conspiracy nut. We should really do more research on the effects of fluoride.

The Takeaway I’m getting from both of these studies being talked about Is that things are very unclear. The Cochrane group is very well regarded for conducting Meta studies and finding flaws in previously held understandings. The term high fluoridation is mentioned many times, and it’s unclear what that is meaning.

Vitamin A is an incredibly important molecule to many biological processes in the human body, but we do not want to supplement it, aggressively, as it can become toxic. Fluoride is noted to be beneficial for enamel hardening. No one is recommending taking large amounts of it. The second link you have points out the important questions, what is the actual danger, and who is in danger the most?