Well, it’s the basis of programming languages. That seems pretty helpful :) Otherwise it’s hard to measure what exactly “real world utility” looks like. What have the other branches of linguistics brought us? What has any human science brought us, really? Even the most empirical one, behavioral psychology, seems hard to correlate with concrete benefits. I guess the best case would be “helps us analyze psychiatric drug efficacy”?

Generally, I absolutely agree that he is not humble in the sense of expressing doubt about his strongly held beliefs. He’s been saying pretty much the same things for decades, and does not give much room for disagreement (and ofc this is all ratcheted up in intensity in his political stances). I’m using humble in a slightly different way, tho: he insists on qualifying basically all of his statements about archaeological anthropology with “we don’t have proof yet” and “this seems likely”, because of his fundamental belief that we’re in a “pre-Galilean” (read: shitty) era of cognitive science.

In other words: he’s absolutely arrogant about his core structural findings and the utility of his program, but he’s humble about the final application of those findings to humanity.

It's a fair point that Chomsky's ideas about grammars are used in parsing programming languages. But linguistics is supposed to deal with natural languages -- what has Chomskyan linguistics accomplished there?

Contrast to the statistical approach. It's easy to point to something like Google translate. If Chomsky's approach gave us a tool like that, I'd have no complaint. But my sense is that it just hasn't panned out.

Who has he mistreated?

Nobody, people are just crying because Chomsky calls them out, rationally, on their intellectual and/or political bullshit, and this behavior is known as projection.