Once you start letting bad people define and box in femininity and womanhood and who is "allowed" to be a woman do you think they're ever going to stop?
In light of the Labour manifesto: Trans rights _are_ women's rights.
I don't mean that in a "Trans Rights Are Human Rights" way, I mean that anti-trans policies are inevitably harmful to all women (as women), and, conversely, that trans-positive norms are a proximal boon to women.
Or any people, really. Let people transition. Let people be what they want to be. Let people live the lives that make them happy and harm no one. For fuck's sake it's their own bodies. Subsidize that shit and let people transition as much as they like. Go full kemmer imo
It's just like trying to gatekeep abortion. Dislike one particular type of abortion? It doesn't matter. Being all in on bodily autonomy protects us all from these creepos and whatever new exciting thing they will use against us all.