Communism in the Soviet Union and Mao's China added a new misery hitherto impossible for the feudal states they supposedly improved upon. The phenomenon of mind control.
Check out "Darkness at Noon" by Koestler. Or the to-the-point comment of Reinaldo Arenas:"although both give you a kick in the ass, in the communist system you have to applaud, while in the capitalist system you can scream."
Don't forget that the Communists under the name of Bolsheviks or People's Army took over by force from actual Democratic / Socialist revolutionaries, and under them misery and death was far greater than under the feudal societies that came from the Nineteenth Century. Think of the body counts from the mass starvation imposed Under Stalin, Mao, and Kim. They run easily into the double digits of millions.
It is incredibly diversionary to put the dead under warfare as anything close to the incredible waste of one's own population as occurred under Communism purely for its own continuance.