But that is exactly the mistake: treating “transwomen” as a separate safe category from men.
Women’s toilets exist because of sex, not because signs magically stop rapists. The point is not that a sign creates a forcefield. The point is that women and girls are entitled to a clear boundary, and staff/police/security need a clear rule to enforce.
Once you say some males may enter female toilets if they identify a certain way, you have removed the boundary for all practical purposes.
The answer is not mixed-sex toilets. It is male, female, and additional single-user provision for anyone who needs privacy, accessibility, family use or neutrality.
Women should not be asked to give up single-sex spaces because public bodies failed to provide enough third spaces.