I think "if you don't have anything interesting to say, don't say anything" is a better metric. I think the problem is comments from people who care deeply,

I think "if you don't have anything interesting to say, don't say anything" is a better metric. I think the problem is comments from people who care deeply, but who are saying things that have been said before, often in comments on the same article. Originality is more important than passion when having a conversation.