Well we can take as a better example that in places like China under Mao and the USR under Stalin there was dehumanization of people oposing the majority an punishing them with prison or worse, it also happen in Nazi germany, dehumanizing people who oppose you is an old tyrant tool, and you cant deny that the US citizen are dehumanizing each other

The exact same universally-human psychology that led to the Holocaust also led to the Holodomor, Mao's Cultural Revolution, the McCarthy era, black lynchings, our modern polarization, and a million other large and small situations where bigots convinced themselves their victims deserved it.