You have to tie your research to the popular causes of the day. It would a bit far-fetched to tie it to gender and underrepresented minorities or online misinformation or covid, so the nearest possible "serious issue of our time" is climate change.
As to why they’ve been like this recently, I can’t tell for sure. I feel like it’s been a bit kore than just a few months though, obviously 2020 was a US election cycle and things tend to get dicey around those times. I recall in both 2016 and 2020 people getting upset by the low quality threads, and other attempted to placate them by swearing it’d be over in a few months. Now it’s been more than a few months at this point, but there was also so much more than an election cycle in 2020 to cause political division.
Which leads to another point. HN is explicitly not a venue for politics, but politics infects everything so it gets complicated. For example, are political threads related to tech and startups off topic? I wouldn’t say no offhand, but there certainly have been an increase in the number of inheritor political threads that I’d personally consider this not the place for. Often this is justified by a lax interpretation of “anything that gratifies one's intellectual curiosity” (note though that the sort of threads I’m thinking of almost never contain inquisitive or intellectual discussion) from the submission guidelines. So if political threads are more common and more accepted, that’s going to invite all the sort of antics you get with internet politics including the sort of comment you mention in your comment. Some of the most egregious stuff will get flagged, but some surprisingly bad comments can stay upvoted if the opinion expressed resonates with enough of the community.
And it's also quite usual that these kinds of press releases have to include some political punchline, to confirm being on the right side of history and so on. It's predictable.
Maybe it's totally benign in this case. But I've been duped so many times that I discount any such claim which ties into these "serious respectable talking points". I'm planning to take a look at Lawrence Krauss' now book on climate change, that dude still seems to have his head screwed on the right way.