Part of the strategy of the Left is to separate communism from its implementation in the Soviet Union, China, Vietnam, etc. The Soviet ideologues set the tone themselves, carefully distinguishing between communist theory and socialist, yet to be "perfected", reality. The fact remains that there has been no humane implementation of a society whose aim would be communism.
It requires crushing the human spirit to be free, independent, own the wealth you create, and own your own body. The communists found they had to constantly "educate" instinctive human yearnings out of people to create "the new man." It didn't work and will never work. I'm astonished that this is not self-evident to mankind and even more astonished where we find our country today.