It's not about defining Woman

While the ruling yesterday says "trans women are men", that's not actually the crucial problem with it. It is a means to an end for organising and permitting harm and discrimination against trans women. The same ruling says that trans men are women. But it rules that trans men's "masculine" characteristics are such that they can be allowed to be banned from "female" group therapy sessions, for instance around abuse.
I know via friends about cases where trans men fleeing domestic violence that started because they came out as trans were told by the women's shelter that they would have to leave if they started taking testosterone because their deepened voice and facial hair may trigger the women they are housed with.
And to be honest those places are often pretty shitty for trans people to deal with, or frankly for anyone. Noone wants to rely on emergency spaces.
But the core issue is that this isn't about who is "really" a man. The state and the toxic British discourse and now the Supreme Court simply use the argument about defining sex in law as an excuse to pass rulings that allow discrimination against trans people full stop.
As a trans woman who has had multiple partners hit me, who has had strange men sexually assault me, I always knew I couldn't rely on those resources in the first place. It was a factor in me becoming homeless back ages ago. I've hosted several homeless trans women in similar situations over the years because that's how we look after each other. That's what discrimination is about. That's what it does. We are made vulnerable to violence because of our gender and our relationship with sex. We are then, because we are trans, denied access to the few facilities for safety that haven't yet been defunded by successive funding cutbacks. On the basis that our faces look weird, our features don't fit a particular beauty standard we are a threat to the mental peace of all the others facing gender based violence we are withdrawn protection. In trans women's case it often includes an element of "unrapeability", the fact that we do not have a uterus means what happens to us does not even count as sexual violence in the eyes of the police, even though the fact people focus sexual violence on us so much more than they do on men is very obviously because of our sexual differences from men.
Frankly this system works on this logic because the patriarchal understanding of rape and sexual violence is one which is based on treating women's reproductive value as property, treating trans men as damaged goods not worth looking after until they can be persuaded to reform themselves into a potential baby incubator and treating trans women as disposable sexual waste you find on porn hub or down the red light district but can't settle with as a wife to mother your kids. Gender based violence is rape culture full stop and it infuses most spaces in society down to how conservative society talks about "protecting women" from those nasty trans freaks. It is proprietorial.
Discrimination law exists, where it exists, to exercise limits on the permission in society for the violence that is allowed to be done. A roll back for these laws is about redrawing the lines of who is permitted to be hurt without sanction. Who is allowed to fall through the cracks.
This is not about defining what is a woman, but who is a citizen in our society with the right to self ownership and autonomy and the integrity of their body and mind. You can tell it is a question of citizenship from the fact that trans people were not allowed to represent our interests in the Supreme Court.
So while yes, trans women are women, and yes we have survived being licensed for attack before and we will survive this too, I would like to ask for people to focus less on the question of trying to define sex more accurately to include us, and more on the importance of ending gender based violence in all its forms no matter who it happens to. Sex isn't a coherent distinction, it has a broad pair of types that are common, but the hierarchy of one of these over the other is forced on to us through human violence, not nature.