" in-group out-group bias.” In 1982, researcher Henry Tajfel divided people into two random groups. He found that people began to favor their random group over people in the other random group (emphasis on random), at times even rationalizing reasons for the other group’s immorality or poor character to justify disliking them.5 "

― Sonya Renee Taylor , The Body Is Not an Apology: The Power of Radical Self-Love