That helps sometimes. Or people try to diffuse the situation by shouting back: Bilbo Baggins 2016 - Free Pies for everyone! - or something somewhat game related. It helps, but there is always trolls that insist on continuing to issue their political opinions, and the heated elections are not helping.
It's not just politics either.... during the superbowl we had an individual who was calling virtually every play of the game. If we wanted to know about what was happening in a sports match that is.... you know, broadcast for free everywhere, don't you think we would have gone and watched it ourselves? He was told that several times by several people, but continued nonetheless. Of course he wasn't breaking any terms of service, and since he never alted (or so it seemed) an ignore did the trick there....
Of course you can't expect harsh moderation and NO offtopic chat..... That's why I would want to suggest to split it in two channels: /world for everything game related, and /offtopic for everything not game related. Make both channels auto-join, and set a rule that anything not game related should go into /offtopic. Now make a "wrong channel for content" report option, and maybe it can be dealt with that way. People can leave the /offtopic channel, and those wanting to discuss offtopic stuff should not do it in /world.
If that can be done, together with an account-wide ignore, I think you solve 90% of problems.