There is a simple reason why John Wayne remains such a beloved Hollywood figure. He is the embodiment of the life story many of us hold as a sacred reality, the ever present struggle between the clearly righteous and the willfully, unrepentant evildoers. It is a sharply drawn picture which glosses over many real world details.
Even during the John Wayne era, some Hollywood productions were more nuanced, depicting their characters as a more realistic mixture of good and bad. However, there was and still is a tendency in the entertainment world to draw a sharp distinction between the good folks who operate with full moral authority and their opponents who have none.
This black-white world picture is the natural outgrowth of a religious tradition in America which unavoidably and unapologetically divides our society and the world at large into to the good and the bad. Of course, "them versus us" thinking is driven by something even more powerful than religious training, since it is almost universal, even among the irreligious. The human ego, with its total focus on self and what benefits me, sets the stage for viewing others as competitors and enemies. Psychologically, that strongly predisposes me to see others as evil people trying to hurt me by taking what I need, want, or already own.
To a large extent, I believe our political polarization derives from the fact that one camp holds to the John Wayne characterization of life in general and another group is awakening to the possibility that reality is not so clear in its good/bad characterizations. The projected simplicity of a previous time can be alluring, but was it real, even then? We should realize that Hollywood was always about selling stories, much more so than showing real life complexities. As much as we might want to live our lives like in those movies, with Bible in one hand and gun in the other, when we attempt to do so, we are forced to ignore or redefine a lot of what we observe. Too much of life is happenstance and not free will determined. That inevitably compromises the black/white and good/bad worldview and its political manifestations.