Short answer: "useful idiots". Just like ISIS that fought Israel's wars against Israel's enemies. Longer answer: History that blames ethnic Russians for the crimes of the USSR, contrary to the reality that the Bolsheviks were largely a Jewish-led minoritarian coalition *against* the majority Russians, much like the US Democrats today. Also a parallel tendency among Russians themselves to Soviet nostalgia - a sort of historical Stockholm Syndrome. Post-Soviet Russians still view WWII in much the same way as normie America: Our boys good, Nazis bad. Ukrainians and Balts contrarily venerate the memory of their collaborators and SS volunteers (as freedom fighters against "Russian" Bolshevik tyranny). Longer still: see this series of articles: https://www.theoccidentalobserver.net/author/rolo-slavski/