Less Than Human - Dehumanization and genocide

"During the Holocaust, Nazis referred to Jews as rats. Hutus involved in the Rwanda genocide called Tutsis cockroaches. Slave owners throughout history considered slaves subhuman animals. In Less Than Human, David Livingstone Smith argues that it's important to define and describe dehumanization, because it's what opens the door for cruelty and genocide. Treating other people like game animals or vermin or dangerous predators."  NPR Talk of the Nation