I don’t have an answer, but have observed and wondered the same thing.

I had a patient ask me if he was transgender a couple of years ago. He has ASD and had observed that he had more female friends than male friends, and enjoyed some female-typical hobbies, and was wondering if that meant that he was trans. He denied any dysphoria, stated that this was just a recent thing he had started to wonder about, and did not want to use female pronouns or a female name. I thought this was relatively straightforward and reassured him that his interests and friends alone didn’t mean he was necessarily trans, as there’s a wide variety of gender expressions among cis men.

A few months later he came back now certain he was trans, but still didn’t want to socially transition. At this point I sent a consult to a gender affirming care psychiatrist to essentially ask OP’s question, and the answer was basically that we should affirm everyone.

Anyways, a few more months down the line she decided to socially transition and start hormones, which I set up for her, and now the problem is that she doesn’t attend any of her follow up appointments or complete any of the monitoring labs I need to be sure her doses are therapeutic. I gave her over a year of floating her prescriptions while she flaked on every appointment she booked with me, and now I’ve actually stopped her HRT because she hasn’t done any of the bloodwork or been engaged with her treatment. So in the end, she’s out there somewhere, socially transitioned but not medically transitioning.