Despite the conjecture, the Nazis were very learned in other cultures (made obvious by their fascination with art and relics) and even adopted a lot of organizational tactics and structures from African tribes.
Not all Nazis were secular, but some of the ones who were Socialists that adopted Fascism (and even many that went on to adopt the even more progressive Nazism) were very secular, like Goebbels and Mussolini, while some where very puritanical, like Hitler and many of the radical youth in their society.
I'll leave you with a critique on Shrier's History Of Nazi Germany from 1961, which is also a great accompaniment to William Shrier's "The Rise and Fall of the Third Reich: A History of Nazi Germany" published a year earlier.