This is like an offshoot of that whole problem where many people will read a story or script and default their mental image of the characters to white males unless other details are explicitly stated. It’s not a conscious thing people are actively trying to impose, it’s just become so deeply ingrained that it doesn’t occur to creators that there’s a box they’re allowed to think outside of. And that’s where the problem is.
Also on Dreamwidth. If you feel like commenting there, go for it. ( other people went for it.)