Nature presents us with many default conditions we can either accept or try to transcend. Ingroups and outgroups in the evolution of animals are about survival and the transmission of genes. With people, those divides are often cultural and not easily reducible to sociobiological terms.

Secular enlightenment in my terms makes for a paradoxical ingroup at best, since that group is alienated from the norms of mass society, including the ideal of being happy and content. At best, that kind of "spiritual" or existentially elevated elite has an exapted function, which is what we'd expect from people that largely evolved out of animality. We took a natural condition and humanized it.