"And regardless of legislation, organisations like Girl Guides and schools are effectively replacing sex with subjective gender identification."
Awful though that is, I don't think it's viable in the long term. At some point, there'll be a group of angry parents who have discovered their teenage daughters have been forced to share a tent with a teenage boy, and they'll be absolutely furious. And they'll sue the arses off the Guides.
It might not be the Guides, it might be something else, but whatever it is, you can bet your bottom dollar that the parents won't go, "Oh, it's fine for my daughter to be sharing with a teenage boy, I mustn't be prejudiced." Because, actually, most normal people who aren't politically active, haven't got a clue that this stuff is going on, and haven't got a clue that objecting to it makes them evil transphobic bigots who deserve to be shot.