Racism as default setting
One of the things I try to get across when I teach race and ethnicity is how much we live in a racist culture where white is associated with goodness, purity, and other good qualities whereas darkness is associated with evil. Based on this dichotomy, we have an entire symbolic repertoire that we are all socialized into. By default, we are all racist, especially those of us who are white. Being racist, not necessarily consciously, is the basic setting. It is NOT being racist that takes work.
How is this default setting socially and culturally produced? Well, through media products, for one. Take the main Disney animated films. Certainly, for the most part of the 20th century, white characters dominated.
Once Disney got into ethnic heroins, their ethnicity was considerably downplayed, just a little ethnic so the audience “gets” that the heroin is not White Anglo, but not too much so that the majority white audience is not unsettled. So, smooth features are the rule. On the other hand, villains are over-ethnicized (if that is a word) so that evil is associated with strong ethnic traits.