Reddit doesn't care if you post repugnant shit as long as it's not child porn and you stay in your little corner of the Internet and don't bother others. /r/CoonTown is a good example of a repository of repugnant shit, but that keeps to themselves. The only reason I even know it exists is because it comes up in discussions of horrible subreddits.
But if you spill out of your little corner of Reddit, then that's when the admins get involved. If you're harassing people on other parts of Reddit, then you see shadowbans. And if you're harassing people offline (doxxing, etc.), then the admins expect the subreddit mods to do something about it. And if the subreddit mods aren't fixing it (deleting the offending content, banning the offending users), then the admins step in and ban the subreddit.
This is a pretty reasonable policy. Some may contend that it's not being applied fairly and equally (ahem SRS), but the policy itself is reasonable.