Answer: Hitler made known his hatred of Communists and the Soviet Union.
Step-by-step explanation:
The Non-Aggression pact between Nazi Germany and Soviet Russia of 1939 was shocking to the world because they thought that the two governments hated each other especially Germany.
The Nazis had mistreated the Communists in Russia, and had made known their dislike of them and perhaps more telling, Hitler, in his best selling book, Mein Kampf, had spoken of the need for Germany to take land from Russia.
It was therefore shocking that such governments would then get into bed with each other.