Re "certain users": I don't see it that way! I'd prefer this to be a place where anyone can post about anything, and if their comment is insightful, that is what matters.
Re "US only": last I checked, US users were only 50% of the community. It may be less than that now.
Re brigading: it's definitely not allowed, and we've worked a lot on trying to stop it, but it's a hard problem.
Re non-technical discussions: I couldn't agree more, and we work hard to encourage that. Even to the point of various secret agendas.
Re sections or categories: no, I don't think that's in HN's DNA. For better or worse, this site is organized around a single front page that everyone sees the same way. Past explanations here if anyone is interested: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...