I’m never going to understand why HN frowns upon humor so much.

Humor is fine. Humor as the only substance of a comment just wastes everyone's time.

Especially when this particular joke is never actually funny.

Me neither. I think the trick is to make it really, really dry and deadpan, then the humourless don't even notice and others have can have a little chuckle.

If you don't quash quips it gets all redditty.

As I have said before in response to similar comments: HN has no problem with humour. Where it differs from, say, typical reddits is that in order to get upvoted rather than dowvoted, humorous comments have to actually be funny.

It's offtopic.