I think it's at least in part because they are completely out of the loop: "[I] realized that in the last year, I have met exactly one person who has [used generative AI] — a writer that used it for synonyms."
The only programmers I "know" using it for work are commenters on HN. I've seen coworkers try and tried myself but so far haven't seen a regular effective use of it except what people describe here.