Before the whole trans debate women were still attacked in toilets though? It isn't as if this is a new thing. The sort of man who dresses up in a skirt with the intention of going in female toilets and sexually assaulting women wasn't put off by the law saying they shouldn't be in there
But if they're there, and they're not supposed to be there, we can a) get them kicked out, and b) back out of the toilet and not go in.
If anyone is allowed in any toilet, we lose what little protection even that provided us. How can we tell if the man in the dress is a predator, or feels they are a woman today?
If you look at a risk/benefit diagram, then what is basically being asked is that women take on all the extra risk, for no benefit to transwomen.
In fact, whilst I can link to numerous changing room and bathroom attacks by men dressed as women, I haven't actually seen anyone provide any evidence of transwomen being attacked in mens toilets. I've seen selfies, talking about how awkward it is, but all the blokes in the background were entirely minding their own business.