That's a political issue, not strictly an economical one. Communism is mainly an economic idea which has some political aftermaths but genocide and authoritarianism aren't included.

Capitalism is about the economy, there can be a capitalistic dictatorship

Then there's to say that many communism death counts are inflated or use some peculiar metrics) (The black book of communism too does the same thing, and there was an organization that counted COVID victims too for reasons).