The first thing that strikes you when watching War of the Century, a documentary about the Soviet experience during World War Two, is how qualitatively and quantitatively different it was from the war in the West. We can say this both in sheer numbers of dead, destruction of cities, and abominable behavior.
Nazi ideology considered the Slavs a sub-human category, and acted accordingly on the battlefield. When Hitler invaded the Soviet Union in 1941, atrocities in the subjugated areas were more than norm than the exception. Jews and communists were singled out for execution, as were civilians for no other reason than the whim of local commanders, or the anarchic tendencies of German troops. Slavs were not fully human, and their lives were cheap.
The people of the Soviet Union were further made to suffer by Stalin, who expected them to sacrifice themselves for the motherland to the point of death. At the end of the documentary, we see a camp where Russian POWs are accused of anti-Soviet activities after their liberation by the Red Army. Most were given lengthy sentences in the gulag.
People on both sides did horrible things on the Eastern Front, and you can watch them explain themselves in this documentary. Very few actually consider themselves war criminal or murderers. In the context of the times, they usually explain, what they did was justified.
And it is hard to judge actions of soldiers in the field based on peace time morality, but if we don’t ask such hard questions, then what are human beings reduced to? Is it really an excuse to say I had no choice, it was part of the time, we were under tremendous pressure? It is difficult to watch an old man, a former Russian solider, smile and chuckle about the rape of German women. How can we forgive this? Should we ever?
Yet more dead and exiled people. More suffering in absolute terms. More people treating other people as mere objects.