In what way does informing children - by virtue of same sex schools - that their sex separates them into two separate categories, help them to learn more about respect for each other?
I think you are being really obtuse here tbh. Girl and boy's schools already exist and the students don't think it's a punitive measure. I don't think it needs to be mandatory but as an option, it's better than simply banging our heads on the walls and saying "no, you're not different from one another" while they continue to blatantly treat each other as though they are.
Also it's not respect for each other, is it. It's boys respecting girls. It's not a mutual disadvantage.
And how is it also not a hostile environment for the boys, both those who will be even more vulnerable in a more male environment, and those who will be indoctrinated into the standard set of beliefs you get with large groups of young men together, in the current culture.
I'm bemused by this. Why is it that you think having girls there would improve things for boys? Is that you acknowledging that boys are more unpleasant than girls? Seems a bit odd. Girls suffer specific things from boys that other boys do not. They are the victims of the sexist behaviour.
And they can learn about respect for women in the same way they learn about most things in school's - theoretically. They will meet women and girls outside of school. It doesn't HAVE to be during school time, conveniently at the crucial time that leads to worse educational outcomes for girls. Those awful beliefs happen in coed schools anyway, girls have never been able to prevent that.
It's not about sacrificing girls. It will be making their lives worse if we intensify sex segregation.
It's sexism women and girls suffer from, not sex segregation. How can you say with any authority that more single sex school's would make things worse?