I would like to offer one explanation for Hitler and World War II that you have probably never heard..
In 1918, near the end of World War I, President Woodrow Wilson, offered the combined Austrian-German armies favorable terms if they surrendered immediately. The idea was for everyone to go home and act as if the war that killed 11 million people never happened. By the time the Austro-German treaty representatives came to the peace table ten months later the treaty terms had changed. They were required to sign a document assuming full responsibility for the war and to pay financial restitution.
After World War I the Austro-German nations were told that the Allies had broken their promise. The anger of the Austro-German people about this "bait and switch" was one of the direct causes of World War II. But the propaganda the Austro-German people were told was a lie. The offer of President Wilson had a time limit on it. Rather than laying down their arms the Austro-German generals ignored the offer, hoping to win the war. When they came to peace negotiations ten months later, the offer had long since been withdrawn.
The moral of the story is- don't believe everything you hear or read.