"You seem to be attributing "motive" to what is just a chemical process. There's no real difference between the reaction that puts Iron into hemoglobin than the reaction that puts flouride into tooth enamel."
There is in that haemoglobin has evolved with iron in it in order specifically to bond with oxygen. It has a purpose and is required for normal bodily function.
Fluroide on the other hand is not required. Fluoride may happen to get into tooth enamel but the tooth enamel is not evolved in order for that to happen. As far as we know anyway. The fluoride ion just happens to replace other ions which are less resistant to decay. It is a straightforward chemical reaction similar to the one that causes those nutters who take coloidal silver to turn black.
So there is a difference.
A silly parallel - take sun-cream SPF chemicals. We could put that in the water of sunny countries so people would absorb it on their skins when in the shower and get less skin cancer. They would benefit and their skin would absorb it. It wouldn't however make it a nutrient. It wouldn't put it in the same bracket as Iron.
Fluoridation is therefore not a nutrient supplement, it is a pharmacological intervention. We are all being dosed up. Personally I don't have a problem with it but I can see why other people do, especially when you consider how difficult it is to be sure that these things are harmless, and how often governments are proven to be wrong about such things years later.