Demonization

Demonization is a technique of villification whereby one assigns demonic, unholy, vile, treacherous, or other bad traits to one's adversary. Often demonization campaigns become so exaggerated that normal everyday people are compared to devils or Satan.

Usually the demonizer is attempting to rationalize some sort of persecution of their enemy. Thus they get others to go along with campaigns of bullying and violence that they wouldn't otherwise participate in.