Why was the soviet union so popular when orwell wrote animal farm?

stalin ordered the assassination of hitler.
the red army defeated the german army.
trotsky and lenin were ambassadors to england.
hitler agreed to peace negotiations with the communist party.

The book reflects events leading up to the Russian Revolution and then into the Soviet Union. The book talked about all the good and bad about the soviet union. So after reading the book many people had clarity on what happened and  should they or should they not support the Soviet Union.

Expostion, rising action, climax, falling action, resolution