I get the notion of not allowing it to devolve, however I do think it should be OK and acceptable to upvote someone for truly making a humorous or clever comment. I work with a lot of clever people in my job, and humor (even bad humor) is part of our daily camaraderie and social interaction, so in some ways it's second nature for me to want to post humorous comments.

Not to over complicate the comment system here but I wish one could just tag a comment as "humor" and one could then choose to just not show them if one did not care to see such things.