The problem is comments that are mean, dumb, and massively upvoted. Or, really, upvoted at all. This suggests that at least part of the problem is the voters,

The problem is comments that are mean, dumb, and massively upvoted. Or, really, upvoted at all. This suggests that at least part of the problem is the voters, who haven't learned that comments of that sort do not belong on HN. I submit the following proposal: If a comment is sufficiently mean/dumb to be killed by flagging or moderators, everyone who upvoted that comment should be penalized and warned