So I have recently been studying what communism actually means, because the apparent contradiction seemed really obvious to me and I wanted to pin it down. In basically every historical example, communism has been synonymous with the state. But if we define communism as purely "the common ownership of the means of production" then there is no need for a state. People can consent to common ownership. That part checks out. What I think is unavoidable is the creation of hierarchies. Some people are going to be better at their jobs than others, and some people are going to have more to say about business decisions than others. The way I see it, if you consent to being part of a company with a hierarchy, then morally that checks out. But if somehow a hierarchy was forced upon you, ie the state, that would be immoral. In the case of the parent-child hierarchy, I think it is reasonable to say parents have special moral responsibility because it's not possible for the child to consent.