Us vs Them Mentality is the reflex to divide the human field into an in-group to protect and an out-group to guard against. It is a direct outgrowth of the illusion of separation and the raw material of the division and conflict trap.
Why it is real and old
This is among the most robust findings in social psychology. Humans form in-group loyalty and out-group suspicion readily — famously, even arbitrary group assignments produce bias within minutes. The tendency had survival value in a tribal past, which is exactly why it is so easily triggered and so readily exploited by anyone who profits from a divided public. The map treats the reflex as genuine, not imagined.
Not dissolving difference, but widening the circle
The answer the layer offers is not to pretend groups don't exist or that all views are equal. It is to keep expanding who counts as "us" until the out-group shrinks toward zero — the move every moral tradition has praised as compassion. That widening does not erase real difference or accountability; it refuses to let difference become a licence to dehumanise.
The tribal reflex is built in and easily used against us; the map's work is patiently enlarging the circle of "us" rather than denying that circles exist.