I noticed a link on my Facebook feed this morning to a Salon article on the "6 reasons religion may do more harm than good." The first reason listed: religion promotes tribalism.
Religion divides insiders from outsiders. Rather than assuming good intentions, adherents often are taught to treat outsiders with suspicion. “Be ye not unequally yoked with unbelievers,” says the Christian Bible. “They wish that you disbelieve as they disbelieve, and then you would be equal; therefore take not to yourselves friends of them,” says the Koran (Sura 4:91).
At best, teachings like these discourage or even forbid the kinds of friendship and intermarriage that help clans and tribes become part of a larger whole. At worst, outsiders are seen as enemies of God and goodness, potential agents of Satan, lacking in morality and not to be trusted. Believers might huddle together, anticipating martyrdom. When simmering tensions erupt, societies fracture along sectarian fault lines.
No fan of tribalism, me, but religion is hardly unique in this tendency.
Case in point: In a link right under the one for that article, I noticed another Salon article, really a book excerpt, on "toxic atheism." In it, atheist Chris Stedman describes the same kind of tribal exclusivity, judgment, and othering among his compatriots.