If I'm running a relay, and there's a possibility that somebody who dislikes me can upload something questionable and use it to make the cops show up at my house and make off with my computers... Well that's content that I'd like to censor.

I'm not taking a stand against the content itself, but as long as there are bullies that can be moved to action by bits on a disk, our protocols will need to either support censorship, of be zero-knowledge to the point where nobody knows which bits are on which disks.