No rule prohibited mass downvoting. Who is to say (retroactively!) that a voter cannot rationally and sincerely determine that the best signal he or she can provide is one that is negative about a particular poster, based on generalizations about the content? E.Y. has advised users that they need not have a rational reason to downvote; not liking something suffices. Well, why not dislike everything by some poster?

Well, I believe the ideal is for users to learn what type of comment other users dislike, and adjust their behavior. If you signal that everything they do is bad, then they can only "adjust their behavior" by leaving the site - and if new users are chased off by this, it's bad for the LessWrong community.

With that said, *I don't think it's reasonable to punish this. The user(s) responsible were, presumably, acting in good faith to improve site, as they saw it. It should be punished *going forward, but banning them will only serve to render their actions even more useless. I wont improve their future actions. I doubt it will even act as a useful signal, compared to an announcement that this is now against the rules.