Proverbs 17:4 Evil people listen to evil ideas, and liars listen to lies.
Have you ever noticed that, generally, in today's society, we are all TOO polite to stop someone from lying or being just plain rude, evil, or hateful?? We are trained to politely listen, to deal with it, and just let the person go on and on...
Well, misery loves company, and sometimes, you just have to tell the person that their hate, their lie, or their other issues are just not something you want to hear. It's not popular, and it isn't easy, but in the long run, it'll set the boundary for you, and you won't have to be a part of something that you later regret.