Ironically I have heard these very arguments before, once, in a movie.
For those of you who don't remember where this is from these are clips from the classic movie Dr. Strangelove.
Now, let us look at Fluoride and where it exists in nature. There is a wonderful little mineral called apatite. Apatite is one of the major components of things we like to call teeth and bones. Apatite is Calcium Phosphate and as a component it also contains one of three ions in it structure. Those three ions are either Fluoride, Chlorine, or a Hydroxide group. Making the final chemical formula Ca10(PO4)6(OH,F,Cl)2