Why do they consider the status of the human body (physical reality)/nature to be the lie and the status of their mind (changeable, subject to mental defect and delusion) to be the truth?
If I think I’m black and I’m lily white, then I’m white (and nuts). If I think I’m Jesus or Napoleon, then I’m nuts.
But if I have a swinging cod between my legs and I think I’m a woman, I’m not nuts.
Freak-show logic, in a nutshell.
Also, the idea that their human body being the wrong gender is a mistake is poor logic. The brain is also another organ, like their genitalia. If they can consider that their body is a mistake, why can they not consider that their brain is also a mistake?
I would posit that extraordinary claims require extraordinary proof.