It's easy to be intimidated by mean people. See through their mask. Underneath is an insecure and unhappy person. They are alienated from others because they are alienated from themselves.

Have compassion for them. Not pity, not condemning, not fear, but compassion. Feel for their suffering. Identify with their core humanity. You might be able to influence them for the good. You might not. Either way your compassion frees you from their destructiveness. And if you would like to help them change, compassion gives you a chance to succeed.