In a former life I ran a company that had forums for our customers that could be viewed by the public. Our policy was to never delete or edit posts. It was great until we had about 2000 customers. Then we got a handful of about 10 nutjobs who formed a small clique to cause trouble. They disagreed with some of our policies & fees, which is fine - we let them have their say about it.
The problem was, instead of just leaving our service after posting their disagreements, they stayed, because they were actually making money from their business with us. But they were so bitter about fee changes, they couldn't let it go. They came to dominate the forum discussion, not because they had anything useful to contribute other than their original disagreements, but because they had a lot of energy to post the same thing over and over.
It devolved into death threats against us, believe it or not, on a forum that we were publishing. How would you handle that in a censor-free environment?