Poe's law. This doesn't seem completely absurd because there are plenty of jerks on planes who don't dim excessively-bright screens much less reduce the volume of crap music.
What's the bar, though? If out of a million people reading a joke, 80% find it funny, 20% find it meh, and one solitary person needs the joke explained to them, I think it's still fair to call it a funny joke. There are multiple comments in this thread missing the satire so it's obvious the percentage is a bit higher than that, but I'd wager the majority of people didn't need the joke explained to them.
HN is not a representative sample of normal people and has a long understood inability to recognize satire, or even just particularly strong sarcasm. HN not getting a joke is not evidence of it being a bad joke.
I've never seen an online community fail to grasp sarcasm as badly as HN. I deliberately make one out of 50 posts ultra-sarcastic (to the point where no normal person could possibly believe I'd hold whatever view I wrote), and they always, always go straight to -4.