The authoritarian personality history
Authoritarian personality forms in childhood through harsh parenting like extremely strict discipline, expectation of absolute loyalty, impossibly high standards and severe criticism. It is also characterised by conditional love (parents love depends entirely on how the child behaves).
These experiences create resentment and hostility in the child, but they cannot express these feelings directly against their parents as they fear reprisals. So the feelings are displaced onto others who are weaker (scapegoating). This is a psychodynamic explanation.