This whole "penis in the changing room" thing that you're hung up on is really an example of"virtue signalling," a term I generally hate as it's so misused although it perfectly encapsulates your whole shtick.
Transgender issues are difficult for almost everyone I think. I don't understand what it is like to deal with these issues. I don't blame you for struggling with it and I'm not saying it's easy.
But your approach, as usual, is to find a victim and propose yourself as the protector, in this case you see yourself charging into the changing room (on horseback? wearing some sort of armor?) to protect the young women (what are they wearing?) from the (disembodied?) penis.
You're ridiculous and both you and J.K. Rowling are simply products of your era and your environment. Don't pretend that it's some holy crusade you're fighting here or that it's based on reason. You operate on emotion, mostly fear of your own inadequacy, and all the endless words you spew about your beliefs are simply a desperate attempt to avoid the truth of this.