You're conflating communism and authoritarianism. Nothing about Communism as a concept requires massacring people. It's just that in the 20th century those who were murderous autocrats used Communism to convince their (often poor) countrymen to give them power and they killed people in service of that power.
Communist and Socialist governments were a popular vehicle for getting poor people to join an uprising in the 20th century and despots took advantage of that.
Maybe that's a distinction without a difference given that we've never really seen a non-authoritarian communist government. But communism has only been around for a century, so it's not out of the realm of reason that there'll be a Communist government that isn't brutal at some point. We certainly have somewhat Socialist governments that treat their people well right now.
Communist and Socialist governments were a popular vehicle for getting poor people to join an uprising in the 20th century and despots took advantage of that.
Maybe that's a distinction without a difference given that we've never really seen a non-authoritarian communist government. But communism has only been around for a century, so it's not out of the realm of reason that there'll be a Communist government that isn't brutal at some point. We certainly have somewhat Socialist governments that treat their people well right now.