I don't think it was the "do what you want with your body" part that generated the opposition. It was a push to make everyone else accept that, for example, a trans woman was exactly equivalent to a woman. Not just in rights, but in all respects. Or the strong push for everyone, trans or not, to make a decision and advertise their own preferred pronouns. It didn't help to then push the philosophy that children, even young ones, should be able to make these kinds of major decisions independent of parental guidance.

If it were just about bodily freedom, nobody would really care. To suggest otherwise is disingenuous. Trans advocacy has very aggressively gone well beyond anything we experienced during the push for LGB equal rights.