I always felt it was important for boys to be able to do things together without girls involved.
At those ages where guys are trying to figure out who and what they are, girls were extraordinarily distracting.
Sure, it could have been just me, but at those ages, girls were a mental wrecking ball for me, and I don’t think I was alone in this. I was nearly girl crazy, couldn’t think of anything else when they were around.
Even in PhysEd classes, even though you were in a class of only guys, there were girls in the same gymnasium or on the next field over.
Boy Scouts rarely had girls around when engaged in activities, and I think that was a good thing to have that outlet as a young guy.
It had been my observation that many young guys changed their behavior when girls were around, including me. Not saying it was good or bad, just reality.
I guess if I had to boil it down, when girls were around, I wanted to get the attention of the girls, but when it was all guys as it was in Boy Scouts, I was trying to get the respect of the other guys.
Those are two very different paths of activity, and the information learned/lessons obtained were very different, and honestly more constructive in Boy Scouts.
The same would be true for girls. Let the Girl Scouts camp, learn skills and earn badges with other girls and without the distraction of attention from boys or trying to get attention from or attract boys. Plenty of time for dating and constant mixing after the high school years when they are young adults, or just separate from scouting time.
Everything in your post is equally true for school.
Boys and girls would ideally have separate primary schools at minimum.
Sex is a major distraction for learning.
The 1960 and on lost at lot of that kind of wisdom.
Men and women are not the same and can not be treated the same.