@Bix They see bigger and stronger women dominating women's sports (as bigger and stronger men dominate men's sports) and conclude "Must be trans!"
But they are all women "assigned at birth". And not one person is crazy enough to change gender just to be better at sports. None.
Most trans people, as small a percentage as they are, aren't good at sports anyway. (as most people aren't)
I'd hazard a guess most men would fail in women's sports, at the elite level at least.