I've thought through the race/discrimination argument many times.
"I am in this body by a biological accident and can express clearly that inside I am a person of the opposite sex to the reality of my external body. To reject me from women's spaces because my body is not what you expect is like white people rejecting black people because their skin is different, or able bodied people rejecting disabled people because their body looks different/ is unpleasant to look at."
I can see where someone in distress regarding their physical reality is coming from, and how they hope that others would be able to set it aside and see them as they want to be seen. I really can.
But the sticking point is the realities and practicalities.
This is about SOME people in male bodies being male and other people in male bodies not being male.
There is no way at all to tell the difference between the one and the other.
The only difference is what that male bodied person (who really does not like having their physical reality referred to) subjectively chooses to say to others about their reality. So it is an entirely trust based situation that relies on the other person being willing to risk and trust on their word.
Isla Bryson, Karen White, Katie Dolotowski all successfully used that trust to injure women. Repeatedly.
How can women logically be expected to extend trust and be the bigger person when inevitably this will end up with some being hurt and exploited? I know the argument is not to punish (by witholding access to women in women's spaces) the innocent because some are guilty, but this is safeguarding. How is it ok to ask women to be open minded about sucking up a rape or two so that male people don't have to cope with the distress of boundaries that protect women?
How can women be permitted to be uncomfortable about and protected in law from being vulnerable and in a state of indignity and undress around SOME male bodied people (on the grounds of them being male bodied) but feel differently about this for other male bodied people? How does this logically work?
We're asking women to predicate their feelings of discomfort, distress, need for privacy, personal boundaries, on what a particular male expresses to them is happening between their ears at the time. Women are supposed to unconditionally trust in this. (And not mind if it turns out later that this trust was misplaced and they got harassed/assaulted/hurt, because of the needs of other males.) There is no reciprocity of respect or even interest in the women's feelings from the male person.
How is this ok? Why should a woman's reality and feelings revolve entirely around what a male tells them he wants them to perceive for his benefit? How is this equality or seeing both parties as equally human? Why is this lack of reciprocity and this unequal responsibility of one to provide for another (who is a total stranger) acceptable and just? Where is the woman's right to boundaries on this? What about consent, some women do willingly consent to this, but what about the ones that don't? Are we going to tell women and little girls, you cannot say no to a man about undressing in front of him no matter how upset or uncomfortable that makes you, if he has certain circumstances that mean you are no longer permitted the right of consent? How does that work in terms of safeguarding?
And yes, ok, setting all that aside, what are we going to do with the women who cannot be in a state of undress or vulnerability with a male bodied person regardless of that male bodied person's inner identity? Where is their inclusion and access? What facilities and adaptations are going to be provided for this to work for them if the goal genuinely is a more equal, tolerant and accessible society?