A very few transsexual males have used female spaces in the past. They had extensive psychiatric treatment and diagnoses. They made a concerted effort to pass as well as they could. And we females pretended to not know they were male, out of compassion and the assumptions that they had removed their male genitals.
The requirement for a diagnosis excluded predators and those with transvestic sexual fetishes. This served to protect females in those single-sex spaces.
Additionally, we as females were empowered to exclude those males at our discretion - we made case by case exceptions and allowed those very few in.
What you're talking about is a complete revision of the situation. Removing the requirement of diagnosis, and allowing policy acknowledgement on the basis of self-declaration means there is no gatekeeper to prevent predators and fetishists. In fact, self-declaration opens a giant gaping loophole that allows predators and fetishists to exploit females on their say-so.
And by making it a policy acknowledgement, it removes the right of females to refuse consent. You've literally set up a situation where females have no right to refuse a naked male in their intimate spaces against their will. Females have no right to refuse consent to a voyeuristic male who wishes to view those females while they are vulnerable.
The policy simultaneously throws open the door to predators and fetishists while removing any right to consent of females.
I have a friend who transitioned many years ago. I first met "her" after her transition and she presents sufficiently female to allow me to perceive her as a "her" even though I know she's male.
She told me all about what happened when she transitioned. (By the way I'm pretty certain she's AGP, she has the background for it, ex-military, but she has never come across as fetishistic to me, and this background didn't stand in her way when she transitioned.)
She described a long process of psychological introspection and counselling before any medical or surgical treatment was initiated. This both served to confirm that she was settled in her desire to transition, and to ground her in reality about what was possible and what wasn't. She always knew she'd be getting only a reasonable facsimile of a female body and would remain male. During all this time there was no question of her going into women's single-sex spaces. That was forbidden until after the actual surgery, and if she'd transgressed on this and been discovered, she'd have been thrown off the transition programme as a danger to women.
She also had quite intensive lessons on how to behave in such a way as to appear as much like a woman, and - perhaps more importantly - to appear unthreatening to women. All this happened long before she was given the green light, post-surgery, to use women's spaces.
She was given a letter to carry explaining that she had been through a process of medical and surgical transition, to produce if things ever got really hairy. However the instruction was to try to perceive if a woman was being made uncomfortable by her presence, and in that case to leave the single-sex space as quickly and unobtrusively as possible.
She was informed that if she got involved in trouble in a single-sex space and made women uncomfortable and didn't leave if that was happening, then the letter would be withdrawn and if she entered women's spaces thereafter she was risking being charged with a breach of the peace or something like that.
Now I don't entirely agree with all this. No women were asked, when these male sexologists decided to give males like my friend "permission" to enter women's spaces. However, the process they adopted was at least somewhat sensitive to women's modesty and probable concerns.
Now we're into a situation where any man at all can go where he likes, and if he's challenged he simply accuses his challenger of transphobia and suddenly he is in possession of all the moral high ground and the distressed women are in danger of being criminalised.