Maybe because the premise is wrong?

Also, if you notice that some group is foundering, doesn't it make you pause and re-examine presumptions about privilege (at least degree of privilege, at least in this context)?

You make a lot of good points (and some ones that I think aren't so good), but the most incongruous part to me is that your characterizations (like the above) seem at odds with your thesis ("if girls are more suited to a school environment, ...").