It does not follow. I haven’t got a strong opinion on transgenderism, but I take the position that it is a physical disorder. Certainly there has to be a disorder somewhere, if it’s not neurological then it is a disorder of some other part of the body. There isn’t anything wrong with gender incongruence, but it is abnormal (a disorder) because most people don’t feel any incongruence between their sex and gender, and there is an overwhelming correlation (not causation!) with a number of mental diseases such as anxiety and depression. No doubt due to the stress of fitting in with a society that frowns upon gender incongruence, which defines gender according to the presence of sex organs.
Whether society should continue to operate that way, that’s a moral question, totally open to debate. And it can be done without assuming that transgender people are mentally ill or subhuman. They can simply disagree about the meaning of gender, and the morals of society.
~Max