The Soviets were in the pleasant habit of not bothering to evacuate their civilians from combat zones, which goes a long way to explain the appalling collateral damage. That the Germans - even perfectly average line troops - had an unpleasant tendency to view Slavs as sub-human helots that could be treated as they felt like didn't help one bit.

ceg, where your argumentation falls short is that you fail to provide even circumstantial proof of Stalin's intent to actually entirely wipe out the populaces that suffered the most under his rule merely due to their race/ethnicity/whatever, as opposed to "merely" killing them in large numbers as means of collective punishement for whatever dubious reason (such as "guilt by association", ie. assumptions of 'treachery' merely for being a member of a troublesome community). What Stalin did was to bloodily crush all opposition to his rule, real or imagined (and he was definitely paranoid), with extreme prejudice and insanely wide coverage with a definite flair for collective punishement; but once he determined this was achieved, the survivors were allowed to live on.

This is oppression, and extremely brutal and bloody at that. But it's not genocide. Genocide is the singular attempt to wipe out an entire population.

There's a difference, athough as far as death tolls go it's often pretty marginal.

Aside from that, Rosa and screwtype are spot on in their assessement of the polar ideological opposition between Nazism (or Fascism in general) and Communism. A good definition I've seen is that Communism, whatever it in practice ended up as, was nonetheless ideologically a developement of the emancipatory and liberal ideas of the Enlightement, albeit taken to extremes (which goes a long way to explain why it bombed; taking even good things to extremes rarely results in anything good). Somewhat perversely one of the most enlightened constitutions in history was passed in the USSR in the early Thirties (which also goes to show how little connection stated principles may have with the practice...), and although the institutions had absolutely no meaning or consequence by themselves the Soviets persisted in maintaining the facades of free democratic elections, constitutional divisions of power and suchlike. Fascism by contrast was at its core singularly the rejection of all such "modern" ideas; the reductio ad absurdum of chauvinism, particularism and reactionarism. It has even been suggested that the reason the assorted Western democracies, also tracing descent from the ideas of the Enlightement, were when the push came to shove willing to ally with the deeply loathed Soviets partly in recognition of this relationship; of two loathsome systems they rather chose the one that wasn't from the ground up built as the rejection of their core ideals.