Dark/light dichotomies, in a religious context, tend to stem from Zoroastrianism, which was the prevailing religion before Christianity reared its head--light means physical light, the flame, the sun, and dark is physical darkness, as in night--in fact, a lot of the ritual and metaphor of Christianity came from Zoroastrianism--but let's not go that way--


I think that looking for ancient origins for racism is a trap--as pointed out, the idea that there might be ancient roots for racism is a way of laying the foundations for its acceptance as an unfortunate part of the human condition--

Racism is a set of lies--beginning with the idea that there is such a thing as "race", and that humans with differing physical characteristics are fundamentally different from one another.

The next lie is that racism is about "race"--it isn't, it's about culture--"racism is a system that justifies the subordination and exploitation of one culture by another.

When you think about it, racism only exists because an educated, literate, and allegedly Christian culture needed to be able to justify all of the nasty aspects of colonialism.

"Barbarians" didn't need an intellectual justification to conquer, they did it because they could--"Christians" have to believe that they dominate because they are morally and intellectually superior--