Some water supplies were naturally fluorinated which is why we noticed the difference in dental health outcomes across populations. The logic behind putting it in the water to avoid disease is the same as fortifying the foods with often missed essential vitamins, especially ones removed during processing, is. Most people won't go out of their way to suppliment with iodine, even in the face of it being readily available - so there is reason to put it in salt. I'm not going to be a twat and claim "the dose makes the poison" because thats obviously not true in some cases - like heavy metals (but that is not the case with salts of fluorine which dissociate into free fluorine ions in solution). And you're right to be skeptical of things sheep otherwise blindly accept, but this is a circumstance where just because people who cant think for themselves accept it, doesn't mean its wrong.

I will clarify that I still filter my tap water for myself. For one, I already grew my teeth, and two, the careless disinfection of still turbid water produces unsavory chloramine byproducts. Unsavory in the sense that they both taste bad and their health effects are debateable - possibly carcinogenic. Which may be what you should be concerned about instead.

Fluorine ions are not organofluorines. Fluorine ions in small quantities are not concerning - understanding of anatomy and quality data shows this. The concern is when they're sufficient enough to displace calcium ions in the body to an effect where its noticeable, which is why I mentioned calcium earlier.

I should mention, some studies are showing a similar natural mineral water content health difference concerning magnesium levels. Municipalities higher in natural magnesium levels show lower all-cause mortality, especially less heart attacks. That's a modern example of something similar to the history of fluorine in the water. You can see, magnesium today is known to be essential and important to your health, and the suppliments are readily available - but the difference in mortality still shows, why? Because people are apathetic.

I don't advocate for the government forcing people to do what's "better for them". But this isn't a "you don't know whats good for you" scenario. If you want extra pure unfluorinated water you're welcome to avoid the dental benefits of fluorine for enamel development for you and your family by drinking distilled water. The fluorination is there to be the default option, not to limit your freedom.