Grammar is the grave of letters.
~ Elbert Hubbard
Whatever the evolutionary basis of religion, the xenophobia it now generates is clearly maladaptive.
Lawrence M. Krauss
Time and again we see leaders and members of religions incite aggression, fanaticism, hate, and xenophobia - even inspire and legitimate violent and bloody conflicts.
Racism, xenophobia and unfair discrimination have spawned slavery, when human beings have bought and sold and owned and branded fellow human beings as if they were so many beasts of burden.
Why do elites hate the poor? It's xenophobia. They don't know any poor people - except their off-the-books Brazilian nanny and illegal immigrant cleaning lady from Upper Revolta who don't speak English.
Xenophobia manifests itself especially against civilizations and cultures that are weak because they lack economic resources, means of subsistence or land. So nomadic people are the first targets of this kind of aggression.