Really? In what way did he "revise" history with his fictional western movie?
Did he revise it more than John Ford? John Wayne? Was that the "history" he revised?
The Classic American Western, sometimes called the Traditional Western, played upon myth and higher spiritual aspirations. In essence, it was an allegory, dramatizing the conflict between good and evil. And in that western and in that conflict, good always emerged triumphant. No, you are right, there is no attempt here at realism, but, in those really good traditional westerns, the filmmakers succeeded in making their efforts convincing. "The Unforgiven" played to a cynic's realism and achieved what it set out to achieve: a sad and serious diminishing of our highest aspirations and our noblest dreams. By reducing myth to commonplace pandering, that film sought to reduce us all to the most common level, the level of petty self-seeking and amoral actions. The Classic American western sought something better in all of us.