the lack of challenge to Clare being in a women's toilet doesn't indicate acceptance and doesn't demonstrate lack of distress caused.
Hi Clare, if you are still here - I appreciate your input and engagement with this - it is a refreshing change to have a less unpleasant tone. However, I wonder if your perception is coloured by your wishes, rather than what is actually happening around you? I do admit, it may be quite tricky for you to get the real view of the women whose spaces you use as most will either quietly say nothing, or if you asked them face to face are socialised to be kind to the extent that they will override their sense of discomfort and tell you it is fine. So I don't necessarily blame you for feeling like it is ok for you to do that (my female socialisation showing there) but some sensitive men have got the hang of erring on the safe side when it comes to their presence around women and I think it would be helpful for you to have the same view.
People who have the benefit of male socialisation throughout their life often find it hard to pick up on the actual feelings of women. They may well only share their objections in a close female circle where they feel comfortable to share, so if you just assume that it is not ok I think that would work better.
I too in all my decades of using loos have never ever seen a woman challenged because she was butch. Women are really good at sexing people in the whole - we have to be for our safety. Neither surgery nor hormones change intrinsic characteristics.
I will add my agreement to this - I know and have known some very butch women but at worst it might take a second glance - I have never come across anyone being challenged and I am surprised about these claims.
In most circumstances I can tell the sex of the person approaching with my back turned, there are so many non-visual clues - the sound and weight of their footsteps/breathing, smell (sometimes picked up unconsciously - pheromones?). As many women say, we are very good at sexing the person near us for a good reason.