Cremation ovens in Auschwitz concentration camp, where up to three million people were murdered by the Nazis (2.5 million gassed, and 500,000 from disease and starvation). By Ari Morgenstern The horrors of Nazi concentration camps did not materialize from thin air. Neither did the shootings in Poway, Calif., or Pittsburgh, Pa.; nor did the hostage-taking in Colleyville, Texas. As the late Holocaust survivor and educator Irving Roth often said: “It began with words.” We must heed that warning now—here in the heartland and from coast to coast—and admonish the poisonous language that inspires hat…