While he didn't specifically denounce Lenin or Mao, he himself exclaimed once, reacting to self-appointed Marxists: "All I know is that I'm not a marxist." That's what I was referencing.
Are you sure you read anarchist theory? Bakunin didn't claim that states "had issues". Here's a quote, for example:
That is because no state, not even the most republican and democratic, not even the pseudo-popular state contemplated by Marx, in essence represents anything but government of the masses from above downward, by an educated and thereby privileged minority which supposedly understands the real interests of the people better than the people themselves.
The USSR was a state-capitalist state, where the bourgeoisy was replaced with bureaucrats - as predicted by Bakunin. If it were truly socialist, it wouldn't have taken away power from the soviets and Lenin wouldn't have abolished unions in favour of his high-modernist ideas.