This isn’t, like, officially a thing. No one demands this. But culturally, it is very much a thing that lots of people only really have friends to which they’re categorically not attracted.

There’s this whole concept of certain friend group activities being gendered, like watching sports is a thing men typically do with other (hetero) men.

Of course, it does also just make friendships less complicated, if it’s clear from the start that no one wants romance.