I genuinely think that was one of the more amusing exchanges I found on HN. There is just such a weird level of.. it could very well be a deadpan joke, but also a well-meaning, helpful response.
This made me realize that I don't mind humor in HN comments when they're genuinely clever.
This is opposed to what you often see on Reddit where the "funny" comments are just chains of some meme/common phrase and display no ingenuity (though, to be fair, I did once find those comments funny).
