One issue that I think causes quite a bit of angst and niggle between posters is when someone is misquoted, particularly when it happens from the same posters again and again. The rules that most have suggested are common sense, however labeling someone racist as an example when the post is clearly just that, isn't defamatory if its accurate. Not easy for the moderators I agree.
Good example is I get labeled a lefty on the political thread consistently when I voted for a right wing party in the last election. ;-)
So someone's lefty might be just right of centre, but not far right as they would like. So what I'm saying is, its subjective.
Anyway its a tough job being a moderator & as long as they are fair they have my full support.