I'm not sure about active censorship, but it could just be an instinctive revulsion. After all, a certain amount of censorship already exists, in that people are not allowed to post pornography or spam or suchlike, and further censorship would simply be an extension of this. Or maybe it wouldn't, since such things tend to be lumped into a special forbidden category but one that is not arbitrarily made up of things with which people disagree. ...I don't have all the answers; I'm going to bed.
I'm not sure how much I agree with the author here. I'm not convinced that active moderation is the only way to preserve the quality of a community.
I think active moderation is the only way to preserve a user experience, but I think that "active moderation" doesn't mean having moderators. I think that Hubski (at present, 223 days after you said this) has the tools to self-moderate, and has a distributed moderation service which is very effective. By being able to carefully control what can come to you and from you, Hubski allows a lot of interesting moderation choices.