Although the WHO report also notes several preconditions, and contraindications, that should be considered prior to drinking water fluoridation, including a few that seem to be obliquely mentioned in the article link, the focus is on maximizing the benefit for the greatest amount of people. Arguably, that's the point of forming a society in the first place.
The stated reason for reducing current fluoridation levels has more to do with an increase in its availability from other sources. But this article is useless in furthering any meaningful discussion so far as it provides little more than unsubstantiated opinion.
It would be great to have a meaningful discussion on how we can balance the benefits to society and individual risks, including exactly where the statistical benefits afforded to a group outweigh the potential risks to individuals. But this article isn't it.
The broader issue touches on exactly how to frame the social contract between a government and its people - what rights are you prepared to give up, what responsibilities will you shoulder, and what risks are you prepared to accept, in order to benefit from the organization and protections afforded by your society?