It's less that he's unaware and more that he intentionally chose a simplistic system, specifically because it speaks to human nature on a far more instinctive level. Joseph Campbell explains it better than I ever could, but in essence Lucas was trying (and succeeded for that matter) to recapture the same sense of epic fantasy that you get from ancient myths and legends. The most basic form of this is the Hero's Journey, as first popularly displayed in the Odyssey.immortalfrieza said:I don't think old Georgie has any idea how real people function, otherwise he would have made the Star Wars universe a much more morally ambiguous place.
Lucas rather clearly, and intentionally, cribbed from such stories to build his universe, and that's one of the reasons it resonates so well with so many people.
That said, I vastly prefer the interpretation of it that seems to be hinted at in TOR and the EU, but is never actually explored in depth because of Lucas. Specifically, that it's less Good and Evil and more Order and Chaos. Similar themes, but distinctly different when you get down to the fine detailing.