Maybe someone could build a forum that enforces civil discussion on political issues, either with automated or manual moderation, but Hacker News' moderation isn't nearly strict enough.
It's interesting that you think so, because this very discussion is extremely political, though perhaps meta-political.
I think Hacker News may be unique in that political discussion can take place in a technical forum.
The main barrier to thoughtful discussion may be the HN points system.
I suspect that many insightful posts are not written due to self-censorship (fear of losing points). It's completely irrational of course, the points are meaningless, but when they are lost it can cause some distress. Nobody likes to lose a game.
Hacker News does not disallow, and but for a brief experiment never has disallowed, political discussion. This non-existent ban does not, therefore, explain HN's quality.
https://news.ycombinator.com/newsguidelines.html
> Off-Topic: Most stories about politics ...
and most people's willingness to support these guidelines with downvotes.