> The glee with which the authors express this sentiment
Author here. It was a joke. I personally don't even notice fonts that much. I had no thought at all of a font substitution feature until Gruber requested it.
Please chill out.
> a poisonous part of the web that I'm glad I don't frequent.
Blogs?
> Instead of being helpful, they emphasize gatekeeping and snobbery.
How was it not helpful? I explained how people could substitute fonts on the web if they want.
This is a classic example of what the HN guidelines tell you not to do: "Please don't pick the most provocative thing in an article or post to complain about in the thread. Find something interesting to respond to instead." It was mostly a technical article explaining how to use @font-face rules.