That statement makes no sense either, the Culture had an explicit department for abusing it's power, Special Circumstances.
I think his point was that even if you live in a post-scarcity anarcho-communist society where everyone is live and let live, the rest of the universe isn't an occasionally you need headbangers.
It's obviously more nuanced than that, but you'll end up in an argument of semantics pretty quickly. All the SC/Mind scheming is ultimately coming down to what we consider to be morally correct, so it'll be a discussion of whether e.g. letting a person die in order to serve a greater good constitutes abuse of power or not. The theme of the Culture series is what we would want to do if we could do anything we wanted, and there's not a clear-cut response to that. The egocentric part of the equation is reduced a lot.
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