You REALLY have never gone to the loo with a friend or colleague have you?
... No, I haven't, because I'm not gay and the idea of urinating in the company of another man is really weird to me.
Men don't gossip in the men's room in your world. Women don't discuss things in the women's room.
Not in my world, in the real world. The full extent of my conversations in the toilet is "hello."
If, for example, a woman I worked with was visibly upset about a male colleague making a ribald remark about her body, I wouldn't follow her into the ladies to encourage her to contact HR .... in your world. In your world, she would just go home and cry.
Your workplace sounds horrible if you work with men like that. I am sorry that your colleagues are such unpleasant people.
Personally, if I saw someone upset by something, I would discuss it with them... In a quiet space or a short corridor. Not in a room where people are urinating or defecating.
We could set up another sex segregated room for things like that, I suppose, but then men would be insisting they needed access to that as well.
What? Why are sex segregated rooms needed in a work place? Are you in primary school or what? Do you live in Saudi Arabia where men and women need to be kept apart?
The example you gave isn't even relevant to the idea of having sex segregated rooms. A male colleague is every bit as capable as a female colleague of comforting a sexually harassed woman and reporting it. You don't need sex segregated areas for a victim of sexual harassment to be helped.