I think you're giving HN too much credit. Threads involving certain topics (e.g. big tech) are completely overrun with snark and hate that I don't see much of the relentless curiosity you're talking about.
It's really sad to see because I love the HN comment section for how easily you can say a thing and everyone understands there's nuance and lots of angles to address the topic.
I've made posts about an app and the author appears curious about the issue (I'm not asking for support, just fun that folks are curious). Other people who understand the complexity (or just that there is complexity) involved are around to explore the issue / ask great questions.
Where other places the response would be the typical cynical "Oh that's just because they want you to upgrade!" and so on.
But this forum is coming up on two decades and has like one or two full-time moderators and somehow remains an island of rational discourse in an Internet full of "I'm trained in gorilla warfare".
It has it's good days and it's bad days, (just as I do as a participant) but I think it's pretty unique.
That said the conversation quality here on the non-hellthreads is still quite high. I enjoyed the thread on C yesterday. It's just that hellthreads and strident comments "feel" like they're becoming the norm here and it's harder to escape from them.