"political power(authority) must be justified"

Got to say that I'm a little skeptical of this characterisation of liberalism since even in Hitler's "mythos" (the most un-"liberal" thinker I could probably think of) did justify his absolute power. Only, he appealed to a mythology of social darwinism and racial superiority, rather than showing how the state would be rationally constructed from a state of nature (which is the project of many early-liberal political philosophers to which you refer).

This also just sounds like Chomsky's characterisation of Anarchism. Although, I suppose, he does sometimes draw from figures like Smith and Mill when talking about political economy on the context of his anarchism. But I don't think that's a good enough reason to conflate them since there's clearly a difference between the core strain of anarchist thought and the core strain of the loose tradition known as "liberalism".