I am finding this debate difficult from both the perspective of a transsexual woman and feeling your desperation not to be stopped from saying what you want.
So I have been trying to look at it from both sides.
I do not prevent anyone using terms like he and male on here with me. It was hard at first because nobody has done that for 45 years - so by the time the surprise wore off I understood why you were doing it and it just seemed odd not nasty.
I knew that it was a point of principle - but others might react differently or not care about the principle just as likely.
Of course, they should - as I do - as biological reality exists.
Though it also is not what you normally get addressed by day to day - especially if you have a GRC and altered birth certificate, which does state Sex Female legally. Whether it should or should not. I was surprised they allowed it too with proper medical support.
Though, of course, only a very small number such changed certificates currently exist.
Personally I would still not insist on any words you use because I think that is unfair when it means a lot to you, for valid reasons. It just seems antagonistic to do so.
As a thought why not try to say what you want in a less negative way.
Then it is much harder for someone to seem reasonable when objecting to your post.
Likely some still will but the fact you have made an effort to anyone looking in will give you the upper hand.
So instead of saying - 'that TIM Abigail Talksalot - he is a male person and can you not just see it in everything he says'.
Write 'of course, that Abigail Talksalot will not really be able to understand our argument here , not being a biological female.
Two things saying much the same, but one does it subtly and will be impossible for the trans woman to dispute without looking silly to any reasonable onlooker.
By not overdoing the argument with multiple negative terms that invite an aggressively negative response, you win by subtlety.
React to the second and they will look silly because you made your point clearly whilst taking care not to be overly personal.