This isn't even transgender (if they were being honest). After all, gender is entirely social. There is no reason to even speak about male and female due to it being a social construct. This is why you don't need either surgery or "passing" to be transgender.

This is someone attempting to refute biological sex entirely.

And also that whole "body/brain" thing is entirely fictious. There is no such thing. The brain doesn't develop a separate sex.