You are right! Single sex toilets were the norm in work places. And the big issue then was not enough, or not enough properly thought out toilets for people with disabilities was the urgent campaign.
So this is again the power TRAs have been given. That because they threaten, agitate, get sympathetic coverage in the media, businesses etc., expect to be sued.
So one again it shows that this is as much about society as a whole thinking that women should just shut up and put up with whatever meets the demands of loud mouths.