Marx argued that the Paris Commune, with its directly elected and recalleable delegates was the first demonstration of the "dictatorship of the proletariat" - by Marx' definition any system where one societal class has control over society was a dictatorship.

Of course one might argue there are many other ideologies that uses other definitions of the term, but there are also many other communist ideologies that argues for even more radical weakening of government control as the first stepping stone towards totally dismantling the state. E.g. libertarian Marxism is a thing.

But whatever one calls the intermediate stages, in any case the point is that when looking at a state-less, class-less endpoint, the distinction is entirely irrelevant.

Nevertheless the Culture was non-heirarchical right from the start. Also is "libertarian Marxism" very different from anarchism? Most anarchists are Marxists.

PS there is an argument that the sheer power of the Minds means that they essentially have had control over humans for a long time, and I am sympathetic to this. However, at least that control is not institutionalised.