bluegrass writes:
...without religion, there would have been no "Gentiles" and no "Jews" in Europe, just people. Religion was and is essential in perpetuating the separate identities.
Without skin, there would be no "caucasians" and "negroes", just (skinless) people. Epidermis is essential in perpetuating the separate of identities. Even a group of people with the same ethnicity, color, religion, and whatever else you might want to include will still find a basis for the separation of identities and some in that group will use that separation as a basis for discrimination, hate, and, given the political will and power, genocide.