> Around the start of Trump's second term, HN reduced the degree to which politics was considered off topic.
That is inaccurate. The standard has remained the same ever since pg changed the name of this site from "Startup News" to "Hacker News", and its focus to intellectual curiosity, coming up on 20 years ago: https://news.ycombinator.com/hackernews.html. You can see there the original language: most stories about politics are off topic (note that the word is "most", not "all"), which is still in the HN guidelines: https://news.ycombinator.com/newsguidelines.html
Arguments about HN having gotten-too-political go back many years, long before the time you're talking about: https://news.ycombinator.com/item?id=17014869. I think there are two reasons for this. One is that there are swings and fluctuations, some of which last for quite a while and give the misimpression that the site has permanently changed. Such swings are inevitable—they are caused by macro trends, which HN is not immune to: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que....
The other is that when people see a series of threads they don't like, or even a single thread they don't like—for example because it offends them politically—they rush to overgeneralize. This applies to all of us and has to do with how our emotions affect our perceptions and thinking.
The one exception to all this was when we tried a "no-politics week" as an experiment back in 2016: https://news.ycombinator.com/item?id=13108404. That experiment failed quickly—its actual effect was to make HN more politicized, so we canceled it after a couple days (https://news.ycombinator.com/item?id=13131251), and reverted to the original tried-and-true (albeit unsatisfactory, in the sense that no one is really satisfied by it—there's something for everyone to dislike) standard.
At first I thought this experiment was what you were referencing, since to this day there are people who occasionally get confused by the fact that we briefly tried it. But when I read more closely I see that you were talking about 8 years later!