Why did communism always turn into a kind of dictatorship?
Afaik this happened with every single instance of a communist country. Communism seems like a pretty good idea on the surface, but then why does it always become autocratic?
Because it is not human nature and has to be forced on people. Eventually even those who are in charge of it fall into the normal human nature of social structures and such.
People will help those they know personally (e.g. family units) and even then only to a point. Harboring resources for yourself is innate. Most organisms exhibit a form of territoriality to protect their resources. Communism breeds apathy, a struggle for resources and hopelessness, just ask anyone who has actually lived through a communist government.