Courts struggle with it too: https://www.youtube.com/watch?v=qhWCk2f2alI
Smaller sites like HN do better compared to twitter or reddit, because it's easier. But ultimately it all depends on what kind of communities the company wants to nurture.
While it would be nice if social media companies actually said the truth about moderation rather than pretending there's some content neutral principals they're applying, I also think a lot of people would be better off if they accept that social media is what it is, and move on if they don't like it.