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 would argue that the opposite is necessary, as a general rule of discourse: we should calmly and confidently talk about politics with anyone and everyone. We should be able to have discussions about things like taxes, the military, and technology, without resorting to screaming and shouting names.
One could make the argument that Hacker News is not a political forum, but I think explicitly discouraging political discourse is not healthy in the long run.