So fucking offensive, and morally and logically incoherent.
It's not the word "woman" that matters, it's the thing the word labels. And all the legal fictions in the world don't change the reality of the things in the world.
We don't want to restrict access to our bodies when we are unclothed to people who use the same label as us. What on earth relevance does a shared label, a shared collection of sounds, have to the physical state of being unclothed? If the name "woman" is truly disconnected from the female body as trans women claim, why should it confer any more right to access unclothed female bodies than any other label we may share with the opposite sex, like "British" or "tired" or "Christmassy"?
We want to restrict access to people who have the same bodies as us because they share the specific vulnerability/quality that is significant in that situation.
That's all, It's that simple.
Everyone understands this even if they pretend not to, even if they pretend that the word "woman" is an opaque barrier behind which no one can see any differences.
So I don't care if trans women and male non-binaries have every single other thing in common with women except their bodies (spoiler, they don't, but even if they did), in the specific instance of bodily vulnerability it's not all those other things that are relevant, it's the body.
If a GRC makes a man a legal "woman" that is not a reason to give him access to unclothed women, it's a reason to say that whatever this word "woman" means, it no longer has anything to do with sex and therefore gives no right to any segregation that was established based on sex.
If law does not currently reflect this simple and obvious truthm, it simply shows that at times the law is indeed an ass.