I think people forget that not only did Russia really suffer from WWII; but also, WWI. The origins of the Revolution saw large swathes occupied by foreign armies, not just Poland but also Belarus, much of the Ukraine and a large and fertile portion of Russia proper. Upon acension to power, they proposed a peace treaty to all other belligerents, were strongly rebuffed by the Western allies and pretty much forced into signing Brest-Litovsk, which stripped away upward of three-quarters of Russia's industrial production, massive amounts of farmland, at the flash of a pen.

I don't think one could imagine such an experience would be forgotten by the early revolutionaries, certainly not Stalin, and what followed should be seen in this light, also, I think.    

The Hun is always either at your throat or at your feet. Winston Churchill