I think HN still tends to reward quick posts over more thoughtful ones. As humor is quicker to post, it will come to dominate (i.e. HN will become Reddit) without this important check/balance in the culture.
As far as value added to the conversation, the joke added more value than the sarcastic passive agressive response did. HN should be more concerned with monday morning quarterbacks than people who add a new facet to the discussion.
