Sarcasm is, by definition, use of irony to be a bit meaner than just make fun of something. It's still irony, and I am not even sure it qualifies for the sarcastic qualities on top.
I find that sarcasm or irony are pretty frequent on HN, or maybe it's just me who thinks it is so. ;-)
It's sarcasm, actually. A rare event here.
Surely, irony is depicted in the open-source, decentralised crowd, berating someone doing something not for money.