I agree with Dan, and I wouldn't have commented had I not read this comment. It's easy to underestimate the happy-but-silent majority.

Dan was spot on when saying that this acidity compounds. It leads to a vicious circle of increasingly hostile comments unless someone decides to be the bigger person and break the chain. Having a neutral third party step in to play this role (i.e. a moderator) makes this chain-breaking far more likely and works to all of our benefit.