Don't bother, he's now unsuccessfully trying to overcome the cognitive dissonance 
Of course Stalin killed 1 billion people. And even more... He personally raped their corpses.
When Hitler occupied Czechoslovakia in 1938 some regions of this country in the same time were occupied by Polish troops. Poland invaded and annexed Zaolzie territory part of Southern Slovakia. Why would you expect one year later in a similar situation the Soviets to act differently?
Because of cognitive dissonance. Only the brave and noble western warriors of light are allowed to act in such way. Fucking dirty evil soviet hordes by definition are forbidden to defend themselves.Of course Stalin killed 1 billion people. And even more... He personally raped their corpses.