[fluoridation]

That's not much an arc, at least as described. He starts with one set of principles, and he stays with those same set of principles, but just changes his methods. A more interesting (IMO) arc would be to realize that principles should be guidelines, not strict rules, and that those guidelines can sometimes be bent in order to accomplish goals. "I can't trust organizations anymore" is not character growth; the character is not learning anything about how his decisions affect the world.