My opinion: because here you can find arguably the highest concentration of powerful and knowledgeable minds, and this is the sort of thing that the world needs working on these hard problems.
I find the concern over serious issues that is often expressed here to be rather disingenuous, as people love to engage in bitch sessions about the bad behavior of the members of their outgroups, but the notion that we should consider rising above that level of behavior and think about trying to find actual solutions is somehow ~inappropriate, as this is a place only for "curious conversation" (except for the exceptions to that rule, of course).
I know HN and dang aren't going to change, they're conservative let's say, and Twitter and Reddit aren't going to change either - and so I am working towards my own solution that I think will allow for adequate moderation and discussion management. I've had 5 years of severe chronic pain, only recently had a surgery that reduced my remaining pain by 25%+ and the specialist was finally able to diagnose 2 other nerve compression syndromes I have, and after those surgeries I believe I'll be able to go full speed ahead with my plans. I'll probably only do a "Show HN" in a year from now, but if you're interested in joining it earlier/once very basic MVP is launched and giving feedback I'd appreciate it; matt@engn.com
I'm not quite sure what people "are", but that there is some sort of a fundamental (and I think unrealized problem) seems unmistakable to me. And I agree that they can't change on their own, but I don't believe that change cannot be coerced - at least, it is highly speculative.
> so I am working towards my own solution that I think will allow for adequate moderation and discussion management.
I am very interested, as I have been working on the same thing (but only conceptually so far), I will send you an email.