I don't know how to find the proper balance of moderation and freedom. I signed up at Jezebel in '08 or '09, when you had to "audition" to be a commenter (which meant you had to leave a couple of comments to prove you weren't a troll or a bot before becoming approved -- it wasn't that hard). Maybe it was simply because of the smaller audience, but I don't remember trolls being much an issue like they have been recently, but I think having to take the extra step to register was a big part of it.
I've been online in some way or another for more than fifteen years. One of the first things I did was join a punk message board. (The running joke was that there were no real "punks"-- real punks wouldn't be wasting time on line, they'd be... out smashing shit or something). Most of the time it was silly, apolitical, and fueled by bad jokes, but I'm grateful I got to cut my teeth there. The moderation was light to practically nonexistent. And unless you wanted to give out your AOL handle, there was no instant messaging. Disagreement was handled "on the board," for better or worse. Most of all, there was a level of respect that I don't see so much anymore.
I'm not so daft that I'd suggest that everyone has a constitutional right to comment on a blog, but excessively heavy handed moderation breeds contempt and insularity. It's why blogs like this one had to happen.