Why do you suppose it's so easy for the government to divide Americans and make them hate ....?

one group over another, i.e., Republicans vs Democrats, Whites vs Blacks, (oh, sorry... don't want to go to jail... African-Americans), Mike Hukabee's vs Ron Paulers, hate against Islam? hate against Iraq? hate against Iran? hate against Syria? Feminists who hate happy women who just want the personal freedom of serving their men, etc? Why do you suppose Americans are so easily enticed to hate whomever the government media tells them to?