... I think this is because it is incomprehensible. It is not possible to understand something that does not make sense.
Given what 'transwoman' means, 'transwomen are women' is analytically false (sc. logically contradictory) if 'women' means 'women', and plainly nonsensical if 'women' is taken to mean something other than 'women'.
Confused about what 'women' means? Well, think of your mother; she was certainly a woman. The mother of my children, she is a woman, as is the mother of any human child; likewise my grown-up daughters. All of them, women. Knowledge of the meaning of such a common word as 'women' is not, as they say, rocket science, at least for a native English speaker.
Do transgender ideologues themselves understand their own claims? No, they do not, at least if they sincerely try to assert 'transwomen are women'. 'Transwomen are women' just cannot be true. At best it can be analytically false; more likely it makes no sense.
I know many such ideologues are very young. Still, though, it strains credulity to think they have no inkling of their own lack of understanding. Why, then, do they keep up their nonsense rather than trying to learn? It would seem we are forced to consider more-or-less nefarious motives. Such as ... ?
Can anyone help me out here?