Quitting HN[1] might have more to do with feeling he and Zig had already harvested the maximum benefit and marketing propaganda usage for elevating itself, including using it to thoroughly smear its C alternative language competitors. Thus, it came time to figuratively give HN the middle finger while on top (selling high before the stock may fall).
Many might not have done a review of the history, as he quit Twitter and Reddit too[2], years ago (2023). Arguably excuses are given to cover for offloading any personal involvement on a particular social media platform, as either they are self sustaining without his presence or no greater benefit is thought to be possible.
[1]: https://news.ycombinator.com/item?id=47928645 (Tell HN: Site Is Trash Now)
[2]: https://andrewkelley.me/post/goodbye-twitter-reddit.html (So Long, Twitter and Reddit)