"The less you respond to negative people the more peaceful your life will become." There is a tempation to fight back, isn't there. To respond like for like. But this only leads to more negativity coming back at you.
Unkind People are pathetic wannabes who foist ugliness onto others to compensate for their lack of self-worth. Ignore them. Engaging them is akin to carrying the albatross for an undeserving piece of waste.