COMMUNISM WAS/IS WORSE THAN NAZISM.
Nazis blamed "inferior races" for all the world's problems. If you lived in Nazi Germany and were unfortunate enough to be of an "inferior race", you knew would eventually be targeted for extermination and you could either accept your fate or get out of the country.
Communists, OTOH, blame pariah "classes" for all the world's problems. The problem with that distinction is that it is completely arbitrary. On any given day, the Father of the Peoples could decide that you are a member of a pariah class, i.e. an "enemy of the people", and have you thrown in a camp or executed. Every citizen of the Soviet Union (even Stalin's closest confidants) was a potential target.
Such arbitrary, capricious, and random TERROR visited on an ENTIRE NATION was the apotheosis of evil.
Which is worse?
A. Killing 6 million people because they are members of a "race" you believe is inferior and inimical to yours.
B. Killing 6 million people more or less arbitrarily selected from the population and designated as "enemies of the people."
The general consensus is that A is worse than B. It gets classified as "genocide," and is considered the ultimate evil.
We don't even have a special word for B, indicating that it is, in many people's mind, not that big a deal.