I also never pretended to know what's in the minds of every Russian, but I know what the school history textbooks in Russia say and I know the attitudes/commentary of the Russian government in regards to the war so I don't have to have lived in Russia to make the observations that I make, just as you don't need to live in America to know that most Americans are technically obese.
Would Stalin been able to have done what he did without his Russian lieutenants and footsoldiers?
I suppose you also feel comfortable claiming that all french love baugettes and cigarettes and making ze sweet love, all british drink tea thrice daily and worship the queen, and all Americans, besides just being obese, also watch reality TV all day and think that the new-age imperialism the U.S. military is engaging in in the Middle East is really a great idea (for the record I actually do). Your example of Americans being obese is an easily researched numerical piece of data, a far cry from the gauging of the general opinion of an entire nation -- not to mention a nation that is probably still afraid of speaking their mind about certain things.
Ask yourself this question: if you saw everyone who dared to speak out against the regime dragged away to Siberia, would you be brave enough to resist when they told you to go off to war?
I'm not a professional Historian, but I don't need to be to be able to tell you that nations get invaded all the time and that Russia is no exception. Saying that Soviet policy was legitimately motivated by a fear of foreign invasion is like saying a British occupation of France would be justified because of the Norman invasion of England in 1066 proves Britain is under the constant threat of invasion.
I didn't justify it, I asked for some attempt at understanding for the causes of it.
And I explicitly said in my post more than once that crimes against humanity are not uniquely a Russian vice, merely that we in the west are much more truthful in our treatment of the past than the Russians are which is a critical moral difference...
If I am open and honest about how I beat the crap out of all of my friends when I get drunk, you'll drink with me because I'm truthful about it? After all, I'm being much more moral by admitting it.