I think the definition of 'transitioning' is key.
What you describe is a person of one sex doing things to themselves, choosing modes of dress usually associated with the other sex - so far so whatever, as long as they are a consenting adult.
But if transitioning means changing sex, as in TWAW, that's simply not possible because humans can't change their sex, so they haven't 'transitioned' at all, they've just taken hormones and bought new outfits. They are still whatever sex they were born as.
The next thing is more problematic - expecting to be treated as if they actually ARE the sex they imitate?
That's unreasonable, because everybody knows [don't they? basic biology!] that you can't change your sex, so somebody claiming to have done so is claiming an impossibility, and it's unreasonable to expect other people - and the law, the media, education, medicine etc. - to go along with something they know to be impossible.
Needless to say, somebody has expressed this better than I ever could:
'Dress however you please. Call yourself whatever you like. Sleep with any consenting adult who’ll have you. Live your best life in peace and security..
Humans can't change sex, and you can't expect people to suspend their knowledge of that fact just to make trans people feel better.