But being a doctor still has a core definition. You're not a doctor if you don't treat sick people or have the ability to treat sick people. There are also peripheral aspects such as how others treat you, or things that most doctors do without this being part of the definition of doctor, but being a doctor is not entirely about those peripheral things. Transsgender (at least in the absence of SRS) doesn't seem to be that way

Or to put it another way, nobody says "I'm a transphysician. I feel like and identify with being a doctor. I want to wear a white coat and have people put "MD" after my name. This makes me a doctor, even though I don't know how to treat sick people."