How do you enforce this? I don't know. It seems to be... subtly enforced in person. How do you enforce it on a website?
I think we have a broader problem with politics; There are many people that I have a lot of respect for technically, who have political ideas I can only describe as 'kooky' - I mean, that's okay, but I don't really want to hear about it, you know? I /really/ don't want to get sucked into that discussion.
I am just as susceptible to the siren song of a political discussion as anyone else; I often find myself writing two-page rants, only to save myself at the last minute by hitting the delete button.
But this might be part of how this is enforced in person. In person, well, the level of vitriol that political discussions have is just not acceptable.
It might be nice place to discuss the legal ecosystem for startups, too.
At the moment I think I would highlight 10 users and killfile 2, and I think both moves would improve my HN experience.