Stalin was certainly one of the more evil dictators in history, and his regime was horrendous, but the concept of communism itself is not.

Burn him! He's a witch!

Cuba is doing quite well as a communist state.

Yeah, Cuba is about the closest thing we have on Earth to paradise...

nor is it within the scope of this argument, I think.

I think it is. Communism is indeed not "kill 'em all." But it doesn't work. It encourages each cog in the communist machine to do the minimum amount to get by, and the government will take care of them just as if they had tried harder. It encourages mediocrity. And they're all dictatorships. Power corrupts, absolute power corrupts absolutely.