I think the other thing about the internet, is it's not equivalent to chatting with your mates down the pub. It just gives everyone a podium, and some of these people point blank do not deserve podiums. Everybody's voice has equal weight and they get to broadcast it at equal volume. In the media, that absolutely wouldn't happen. A racist TV programme, for example, would not be broadcast. A racist post very possibly could. There's no filter - which becomes especially obvious when people start to think they're chatting, rather than broadcasting, whereas in truth it's really a bit of both.
Every post you make on the internet is a broadcast. A conversational one, sure, but it's a permanent document of your opinion at the time. And if you deserve to be taken off the air for it, you'll be taken off the air for it.
Moderators aren't exactly Ofcom, but they aren't exactly your mates either. It's a nice medium between natter and broadcasting. There are websites which have policies that I personally disagree with, and I don't end up posting on them very often. There's a certain Dream Theater fansite (ex-Dream Theater fansite, now, in fact), where a couple too many of my posts have wound up in the bermuda triangle and I've just decided it's too draconian. But it's their prerogative. I don't whinge, I just vote with my feet.
You've got to find the right middle ground for yourself, I feel. I like to go on websites where I don't feel like any old idiot can croon about their own half-baked opinions, I like to go places where proper discussion is fostered, so I'm usually grateful for moderation, rather than resentful of it.