I believe that as early as 1919, dealing with ethnic minorities by means of extermination was an option on the German Fascists’ table. (Warning: racism.) There were occasional hints at this in the ’20s and ’30s, like when Adolf Schicklgruber wrote in his book that ‘The nationalization of the masses can be successfully achieved only if, in the positive struggle to win the soul of the people, those who spread the international poison among them are exterminated.’

Later in 1933, a Fascist article unambiguously stated that ‘The Jewish people must be exterminated from the face of the earth.’ The possibility certainly worried Franz Werfel (alav hashalom), who was upset about the Central Powers’ attempted annihilation of the Armenians, which almost certainly inspired the Fascists.

what about the schlub who repaired people’s plumbing?

Even if he were somehow ignorant of the NSDAP’s white supremacy, he still benefitted from it: antisemitism freed up more employment opportunities for gentiles, eliminated Jewish competitors, and forced Jews (and legally ‘Jewish’ people) to soak up capitalism’s consequences, such as inflation and high taxes. The Fascist bourgeoisie also benefitted quite nicely from cheap Jewish labor, and even businessmen who saved Jews still contributed to the Axis war machine.