I have a motivational card I made for myself. "I don't have to explain or excuse myself to anyone."
As empowering as it can be to stand up for oneself, it can also be empowering to let crazy, evil people live in the mental squalor they've embraced for themselves. Neither you nor I live in the hateful, scared world that this poor man lives in, and he created this world inside his own mind.
Meanwhile, your mind is filled with helpful and productive thoughts. If you can, find it within yourself to feel sorry for this sick man, who cannot feel happiness for others or for himself. He's a sad, little man, trying to make other people sad and little along with him.
Rock on with your bad self. YOU are awesome. YOU are amazing. YOU are powerful and strong.