My half baked answer to all of these questions is that people stake out extreme (and often incoherent) opinions like these simply to signal that they’re in the right tribe.
Perhaps I’m naive, but I’d like to think that if given truth serum, everyone would agree that, yeah, there’s nothing actually wrong with a Japanese company selling Kimonos to white people, or a Chinese movie production hiring a white guy, or whatever. But if you’re trying to present yourself as a certain type of person online, you’re not going to do that by acknowledging tradeoffs or nuances. You’re going to do it by showing that you’re fully dedicated to The Cause. People observe others doing this and react by going even further in the hardline social justice direction, and things eventual spiral into silliness.
Like I said, that’s a half-baked theory, but it makes a modicum of sense to me at least.