Huh? 
Who was saying that Stalin ‘“freed”’ (note double quotation marks) or even was trying to free anyone in WWII?  Certainly not I -- that notion is historically absurd.
Hitler’s Germany invaded the Soviet Union in 1941, not the other way around.
Yes, after the loss of 25 million lives and 5 or 6 times the number of US soldiers sacrificed, Hitler was defeated (mainly by the Soviets with some help from other Allies, actually), and Stalin gained control of the German-conquered E. European states. But this was the outcome of the all-Allies’ post-victory doings at Yalta involving Churchill, Roosevelt, Stalin and Smuts (in which the non-Soviet victors all gained vast swaths of the rest of the shortlived German/Axis Empire, and more).
And yes, Stalin was then an oppressor-butcher, not a liberator, in Russia and the rest of the Soviet Union.  Who said otherwise? — not I. Such a notion is also factually absurd.
My simple point: Stalin was evil, yes, but the world owes him one too.