The difference, the Commies murdered millions more than the Nazis, but were smart enough to destroy most of the evidence, and hid the bodies that are now being discovered. If given power, they (Communists) would do it again, with no remorse. One party control means no limit to their power. The Nazis copied the camps from Russia. Ever notice there are maps showing the Nazi camps, but very few ever show the Stalin era camps. Judging from the scale of people forced to die in the USSR there isn’t enough room for all the dots. If anyone brings that up, the left immediately accuses you of being a Nazi sympathizer. Russia could never pay reparations for all those who were sent away to disappear, or just murdered on the spot. (They called voiced political dissent treason.) Both systems were based on terror to control the population. If you use terror and forced labor, you are not for freedom. Those who use terror will promise you milk and honey in life, but they only deliver fire and brimstone, and repeat the darkest part of history. Nazis and Communism, same crap in different wrapper but one comes in the larger King size package.
And under Stalin, there was plenty of ethnic cleansing, as communities were completely uprooted and sent to Siberia, to be replaced with ethnic Russians.