"My advice in this case would be to create a moderator stream that the end users can subscribe to."
That sounds like a pretty complex thing to do, which doesn't solve the problem of, "The comments on my site are overrun with people posting racial slurs."
"In this case the site owners would be able to moderate comments through voluntary cooperation with its users, but it wouldn't be able to censor opinions that it didn't agree with, because the end users would always be in control of how its stream is filtered and would always be able to verify that on-topic posts aren't censored."
I don't believe that's actually a problem, though. You can always go make your own site if you want your voice heard.