How do you deal with them? With patience and honesty. You talk politics, make it OK to discuss things without demonizing people who disagree with you. If it’s impolite to discuss politics, then only the impolite will share their political opinions. And you know who benefits? The fascist. They want the opposition silenced by propriety. They want the extremes to be the loudest voices, because it paints the picture that both sides are unreasonable.
Don’t avoid the subject. Dive headfirst into it, and be prepared to resist the urge to roll your eyes or get emotional. Be calm, be rational, and be direct. Conservativism is a fungus that grows in the darkness. In the conservative mind, they are the heroes, and everyone else is evil. You won’t win that debate with logic. You have to use the gray rock method, and prove to them that you both disagree with them, and you are not their enemy.