Anti-Semitism has a long tradition, and is not limited to Germany. But here it is radicalized by National Socialism, popularized with effective slogans, and – for the first time in history – elevated to the rank of a state program.
Nazi racism, an ideological waste product of the worldwide scientific enlightenment, divides people into "creative and destructive" races of differing worth. It thus reinforces the notion that nature has thrust individuals, peoples and races into a perpetual struggle for survival in which the "weak" and "sick" will be destroyed by the "strong" and "healthy."
In this deluded configuration, the Jews count as a population of parasites trying to destroy the "valuable" peoples from within. After the 1917 October Revolution in Russia, this notion is expanded with the idea that Bolshevism is a tool of the Jewish campaign for world domination. And thus is born the "Jewish-Bolshevik world enemy."
Racist persecution under the Third Reich victimizes not only Jews, but also Sinti and Roma. And it can also turn against the Germans' own "race": any genetic material considered less worthy is to be cast out from the "hereditary stream" of the German people; life that is "unworthy to live" must be destroyed.
Ultimately, the war eliminates all inhibitions against a "biological" solution of purportedly biological problems. Limited campaigns of murder become campaigns of "extirpation" which in their turn – in the fall of 1941 – become systematic genocide.