Rosabeth Moss Kanter

Tribalism reflects strong ethnic or cultural identities that separate members of one group from another, making them loyal to people like them and suspicious of outsiders, which undermines efforts to forge common cause across groups.

Like the 'little emperors' of one-child China, too many Boomers were taught early that the world was made (or saved) for their comfort and enjoyment. They behaved accordingly, with a self-indulgence that was wholly rational, given their situation.