Regardless of what you think about Marxist concepts themselves (or their feasibility) Marxism/Communism requires the "withering away of the state." So long as there is entrenched leadership, that society is not leftist in the same way the Nazis were not socialist, and Republicans are not "pro-life". And yes, that means the USSR was right wing, not left. At no point did the USSR meet the criteria or definition of communism. The definitions lead to the label, not the other way around.
I have disagreed with almost everything you have said, and am likely a member of the group you are railing against in this discussion. However, IMO you are spot on here.