Spending time studying the first-hand material of the NSDAP (magazines and the like) I've noticed a disturbing pattern.
The amount of material from before the war is slim pickings. It's in some cases impossible to find things published before 1934 that aren't locked away in university libraries by academic appointment only or available sparingly through biased excerpt translations.
Makes you think what exactly is being hidden away... probably some great strategy and actionable guidance
Much like the Jews in Jesus' day they don't want any cross-examination or scrutiny because it puts them in a catch-22 situation. Just believe them when they say "if [insert verboten topic here was not an evil, we would not have said it was evil."