I've been part of this community, and slashdot before it, for more than 20 years. The shifts in attitude are huge.
To start with a tech-focused example: there used to be at least a sizeable minority in favour of GPL licensing, vs. MIT, and people on both sides of the issue had at least some familiarity with it. Today, I see comments where people seem unable to even grasp the idea that anyone would consider the GPL.
Since it's difficult to believe someone would actually forget so much on an issue of importance to them, I believe it's changing audiences rather than the initial audience getting older. Or, alternatively, the tech sector simply expanding by several orders of magnitude, and any people who have been in it being drowned out.
This is somewhat noticeable on issues of social justice: all the major tech companies still have policies to promote participation by groups that were traditionally marginalised. But you wouldn't expect that from the comments here, Gamergate would still be filed in the ethics-in-journalism-dept', if that joke had survived.
It's tame in that people will opine that women are too stupid for IT, but they will do so very politely.
HN moderators are very proud of being accused at roughly equal rates from both of the US political tribes. That's the sort of triangulation leading to false balance even local journalists have managed to pick up over the last decade, where they still exist.
I'd really prefer if they flipped a coin and grew a spine. Is George Soros eating babies or not? Answering that question with a shrug isn't neutrality. For anyone in a position of even minor power over the discourse, it's dereliction of duty.
Practically, it means that any even barely political question on HN is discussed on a level where I could write both sides of the discourse in my sleep. If it's SF housing it's going to be "you don't want homeless people around where you life if you have children" vs. "you do know not all homeless people are violent, right?".
In the process, everyone retreats to their corners. The "virus lab leak" idea, in its first incarnation, was not something I'd be willing to explore, because allowing any possibility of it would immediately be weaponised by people pushing the idea that it was an intentional release of a biological weapon, an idea with completely different ramifications that was, nonetheless, superficially similar and closely linked.
Any tread on COVID is 90% fighting over "it's just the flu" (very beginning), then hydroxywhatever, and lately ivermectinopleasedont. In that regard, I truly doubt the comments are representative of even the readership of HN, let alone the US public, and even less the world's public.
Opinion on "mainstream media" is probably the most out-of-wack compared to opinions generally voiced in polite company. It's enough for a story to be published by the NYT to get a dozen comments often not even arguing that, but assuming everyone agrees with, the idea that everything they write is a lie. This may be an outcrop of the single uniting characteristic of commenters: they love to be contrarian. So much so, on this issue they all agree. "Actually", they tell each other with the mannerisms of a big truth being revealed, "I am much too smart to believe what everyone is believing". And if that means water isn't wet, so be it.