Seriously I don't get that

I bet its the former

As a guy, i can say, yeah probably

Former as in we just like dividing stuff

could also be a numbers thing, too many people in one league would slow things down a bit.

Especially in the case of E-Leagues. You look at the guys playing those games, they've been gaming their whole lives. But women, many of them haven't had that opportunity. Instead of just saying "git gud" they have male and female leagues so encourage them to participate. You need to start somewhere before things will change.