An interesting discussion from quora, Why do people perceive the USSR as less evil than Nazi Germany?
Also, Jordan Peterson addresses this question a lot, too, as to why Nazism is perceived as being worse than Communism even though the latter has a higher death toll.
The most parsimonious explanation is that the Nazis lost and the winners get to write themselves in as the ‘good guys’.
Another reason is Communism is predicated on ‘class struggle’ whereas Nazism is about racial purity, the later which is inimical to the left, who are more sympathetic to Communist ’cause’ of class equality, despite the tens of millions of deaths. For example, the belief that Communist deaths were the result of ‘bad policy’ or ‘mistakes’ rather than deliberate malice and racism, in spite of the fact that Communists did in fact persecute groups, particularly intellectuals and counter-revolutionaries (or anyone a threat to the state apparatus). Although some argue totalitarian is not the same Communism; however, stale-less communism is a myth. In order to ‘liberate’ the proletariat, a lot of people have to die. Ironically after WW2, intellectuals (the very group target by Communists, particularly the Khmer Rouge) would later disseminate cultural Marxism (technically called the Frankfurt School and Critical Theory) throughout colleges, brainwashing generations to believe the misconception that Maoism or Stalinism was a ‘lesser evil’ or more ‘humane’ than Nazism.
But you also occasionally see Conservatives ascribe the label ‘fascist’ or ‘Nazi’ to their intellectual or political opponents, suggesting this belief in the unalloyed evil of Nazism transcends party lines. But why, again, is it so bad. Why does Nazism scare so many people, both liberal and conservative.
My theory is that Nazism, perhaps, is seen as a ‘perversion’ of Western civilization (a version of Western civilization in overdrive, taken to its most extreme form), in much the same way cancer is a perversion of otherwise healthy human cells. Maoism and Stalinism, both ideologies of the ‘East’, are categorically different than Nazism, which originated in the ‘West’, hence the ‘leap’ from America as it is now to Nazism is shorter than the leap to Communism. I don’t agree with this paranoia…If you consider the post-60′s rise of social liberalism, we’re closer to Communism than Nazism.