[PeterisP]

IDK, in communist regimes generally it was the regime that was the evil part, not the economic system.

USSR bolshevism was just as evil (or even more so) during their 'new economic policy' (free market capitalism) years.

Revolutions establishing de facto dictatorships were just as evil as any other dictatorships, no matter if their economic policy in the end was communism, fascism or free market.

Revolutions creating a one party communist state were just as evil as revolutions creating a one party theocratic state or one of the many cult-of-personality fascist regimes that happened also long after ww2.

Revolutions or coups establishing oligarchies or committees running everything were, again, just as evil no matter what economic policy they run.

The evil of one group gaining power and slaughtering another group is the same no matter if the "othering" happened because of class warfare, religious hatred or ethnic cleansing.

It's just that in the 20th century communism was the most popular cause of regime changes resulting in such dictatorships and single ruling party systems, though nowhere near the only one.