Ask Lemmy

In Russia it's because of the cult of personality, or populism, that developed around Lenin and Stalin. Mao in China, pretty similar. You should appreciate how a country falls into chaos and madness when a populist takes power and ignores all legal and cultural norms and gets away with doing whatever they want.

Ultimately, it's because the foundational ideas of communism don't scale.

in theory communism makes resources the property of everyone. In practice, somebody has to manage the resources, and in doing so controls them. if you control the resources, and especially if you have the power to defend that control, you effectively own them. this means that while in theory the people own everything, the truth is that the government owns everything. by similar logic to the first bit, if they own everything then they have control of everything, meaning that they are authoritarian. that being one of the major defining characteristics of a dictator its not far from there to become one even if you aren't trying to. ironically, this is all how it's intended to work save for the dictator part. this is the apple mouse charging port of communism, an intentional thing with a bad result that can't be given up without invalidateing things you have said or done.

also, communism tends to be brought about by coups and coups tend to lead to authoritarian leaders, compounding the above issue.

Because it was spread by a totalitarian communist dictatorship. if the USSR were democratic , they wouldve spread democracy.

because its a centralized system with well defined hierarchies. makes it incredibly easy to subvert and control.

Because the Soviet Union was autocratic and communist/socialist countries had to choose between cosying up to them and being destroyed by the CIA.

Because thats the end result of embiggening the state: The state gets bigger, and the oligarchs just changes faces.

It was something Marx remarked on later, post Paris Commune.

You can really ask the same question about capitalist societies. Why is there such oppression? Why is there a group that can do anything and a group that cannot? Regardless of your political system, human behavior is the same and it usually involves insecure ape-like people who want power for power's sake. Communism, just like every political system ever created, trends towards this sort of behavior.

As someone else said, desperation will cause people to move towards authoritarian thought, be that the extreme right (fascism) or the extreme left (communism).