That's easy to answer -- humor is almost always disparaged at HN. People want serious discussions, and jokes often end up being noise blocking the signal. Also

That's easy to answer -- humor is almost always disparaged at HN. People want serious discussions, and jokes often end up being noise blocking the signal. Also, sarcasm by its ambiguity requires people to shift gears from a straight interpretation of someone's post, to one in which various kinds of verbal trickery is intended. It just seems like too much work if a straight presentation would convey the meaning more efficiently.