I think the ban was justified because of the number of people targeted. Going after one person is bad, but vendettas are understandable (if not approved). But going after huge amounts of people... Well, there we have to multiply.

Why? Seriously asking. I see no evidence that we were somehow powerless to stop this without banning him.

But if that were the case I would definitely be in favor of doing so.

As for those deploring the ban, I can see your deontological position, but do you think that Less Wrong is going to become measurably worse because of this decision?

Well ... yeah. Worse by one user.

(It's not as if his contributions were terrible, remember, a troll that we're well rid of - Eugine was a high-karma user, that's how he was able to downvote so many comments.)