So I'd say that because of how the "hivemind" thing works on reddit, generally the racism and xenophobia is more accepted and common as it's just seen as the right think. Of course there is also definitely subs that go out of their way to be racist/edgy-- so bad that other redditors think it's too racist for them.

Like even in real life, there are many liberals or even "progressives" that hold some pretty racist views. Whether it's closeted or not, there are definitely people who don't think they hold any problematic views thinking they're anything but racist. There is just some narratives that stick to big groups of people that don't consider themselves holding racist or xenophobic views.

It's really hard to say if reddit, Facebook or YouTube have more or less racism, I think it's possible to be worst in some areas than others. like outwardly nazi content creators are absolutely going to have vile shit in their comments. But you can also be blind sided by seeing it in areas you wouldn't expect.