The original question at stake here was why western Europe would want protection from Soviet invasion. I have provided a list of reasons. Should probably have put it earlier in the comment chain, but you haven’t even pretended to adress it. I do acrually have some synpathy for your argument of the necessity of the USSR accepting the Molotov-Ribbentropp in the face of the weatern allies’ refusal, but I still find it a rather weak argument considering how completely unprepared the USSR was when Barbarossa began, because they don’t seem to have accomplished much with their vaunted breathing room. Not that any of this justifies the decades of occupation and oppression after the war.

And how do you explain Holodomor? Katyn? The Winter war? The annexation of the Baltic states? The Prague coup? The suppression of the Hungarian revolution? The suppression of the Prague spring? How does the Nazis being worse justify the authoritarian and imperialist things the USSR did?