Soviet leaders had no choice. In 1920 the country was destroyed by civil war. Industry was absent. The people were starving. Society was split. Nobody has experience living without a Tsar. Nations within the country did not like each other. Fascism was arising in Europe, militarism in Asia. Everyone knew that time was short. The Soviet Union had to create powerful industry or be destroyed (and the apocalypse came very soon - in 1941). People did what they should and did not pay attention to stupidity, cruelty and injustice. All of this was secondary problem. Sovet Union managed to force Hitler to get stuck and retreat before Normandy landings. If it could not, Hitler would receive all resources of Russia and then the apocalypse would come to Great Britain and the USA...