And before Hitler there was the Terror in France, the Bolsheviks in Russia, the Communists, Socialists, and Anarcho-Syndicalists in Spain, the Christero War in Mexico, Mao, Ho, Castro, Pol Pot. It never ends. They all go for the religious first because they cannot abide being compared to an absolute moral standard.
To put it bluntly they enjoy getting yanked around by hell.