In the current broadly divided political environment, it's a juggernaut with a mind of its own. In the real world it seems rare to have a conversation about damn near anything without politics coming into it.
You know what might help? Why not allow a few free politics boards? Much of the political discussion on stock boards now is started by free users who'd like to indulge in political chat. Yes, of course those free users could just pay for a sub, but I have the feeling they mostly don't do that.
So why not let them post on the existing politics boards, or create new ones for them?