As I said those are not communist states and therefore do not represent communist ideology. As you say those examples all had a tyrannical leader and communism does not support the idea of tyranny, dictatorship of the proletariat is the only dictatorship acceptable and therefore those states do not represent communism. It's easy to throw around numbers of deaths and blame it on communism but that is the fault of the dictator not of communist ideology. Deaths in the name of capitalism (1 million Vietcong/NVA killed by American intervention in Vietnam), fascism (6 million Jews killed by nazism) and other ideologies are just as awful so why is only communism seen as a killer? As for "communism is incompatible with how people actually behave", humans adapt to whatever environment they're in, people are capable of the altruism needed to support communism when they are put in that environment so your point is incorrect. The revolution is inevitable and I hope you achieve your class consciousness sooner rather than later.