Dank, this is the one and only time I've actually agreed with what you're saying. Even if fluoride wasn't dangerous, there's no need to keep it in water, when it's been proven not to be beneficial when ingested. That's suspicious.
Let's play a game. You figure out why they put fluoride in the water and post it here, and i'll give you $5.
Gross, what would I do with $5?
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But in all honesty, from what I've come to understand, it's a by-product of industry. The folks who advocate fluoridated water must be paid off or something, because the type of beneficial fluoride (I believe it's called Calcium Fluoride) that is naturally found in water is not the same type of fluoride they're dumping into the water supplies (I believe this one is called Sodium Fluoride. Confused me at first, because I thought this was the same thing as table salt (or is it?)) So, instead of disposing the waste properly, they dump it into the water supply and call it healthy for your teeth. In this case, it's an issue with profits.
On the other hand, there's also suspicion that it's being used as a social experiment. Purportedly, the sodium fluoride causes people (among a slew of negative health effects) to be much more tame and docile. If there's any method someone would employ to control not just one society, but any society they saw fit, they would insist that putting sodium fluoride into the water supply was great for your teeth (even though there's been studies that show non-fluoridated water has no positive effect on teeth.) I could be wrong, but this started...1920's? 1950's? One of the two. And I've noticed there's been few uprisings in America despite a lot of horse shit lately. Whenever I hear someone say "Wake up, America," I find it funny that they chose those words specifically. Also, apparently Hitler used the same method to calm prisoners in prison camps, to prevent uprisings.
Whichever one you wanna roll with, I suppose. I'm inclined to believe the reasons are more likely to be complex, as there is not just one person with one mind running America, but rather many, and many minds have many interests. So both may be true, depending on who you ask. I just don't buy into the "it's great for your teeth" game.