Reddit routinely shadowbans me and roommates because we'll see a post on /r/all and comment on it. It was way worse when I lived in a dorm. My upvotes/downvotes and submissions were completely broken. Took months for whatever anti-abuse system they have to unflag me.

Their anti-abuse is really bad. I once reported a serious doxxing with a death threat towards another user and after three weeks received a canned message saying something along the lines of 'Sorry, there's nothing we can do about the post. It will stay up.' This was circa 2019, when they already had a formalized 'anti-abuse' team. What exactly they do, I have no idea.