[Amake]

I'm with Einstein: "'Common sense' is the sum of all prejudices one has accumulated by the age of 20."

Territorial aggression may be an instinct, but indulging in it, as well as channeling it into thinking less of people X are learned skills.

Searing insight edit: It occurred to me that as far as we know humans never marked their territory, in any way, until long after the words for "territory" was invented. Even now we have no clear definition of what it is. We have personal spaces that may be any size, neighborhoods that may or may not be marked by spray paint, internationally acknowledged national boundaries overlapping with cultural and economic ones. Maybe our entire history of oppressing minorities and condemning people who are different in any way is just misdirected frustration because we never learned to pee on trees.