The way this sounds is that you are more concerned about politics as in people who take party positions and may feel excluded as a group when the majority of the community takes a different position. This is a slightly different issue i.e. party politics, and I think it is fine/a good thing, but it is also important to distinguish the two. This should essentially be under the same umbrella as personal attacks, as they are essentially the same thing.
I don't feel this need to be an explicit policy. I mean it gets into the entire "what is politics debate."
Hackernews is about hacking (software, hardware, life), and I still see tons of that on here -- well that and Amazon spam, but that's mostly due to their recent conference/product announcements and will probably die down soon.
That is all anecdotal of course.
edit: grammar.