The correct answer is scapegoat theory
Scapegoat theory is a term from social psychology that relates to prejudice. According to this theory, people may be prejudiced against a group in order to vent their anger. In essence, they use the group they don't like as a target for all their anger ... as a vent.
An example that has been suggested is the holocaust. According to the scapegoat theory, the Germans used Jews as scapegoats for all their problems (which included economic problems across the country). With the focus of all their anger on the Jews, they let their anger and hatred flow, and they concentrated all their anger, frustration, and problems on the Jews.