[indymike]

> Nor is there historical evidence.

Migratory hunter-gatherer tribes have spawned some of the worlds "greatest" conquests - a good example would be the Mongols (who to this day hold the record for largest empire by geography). If it were just Genghis Kahn, that would be the exception that proves the rule, but there a lot more. https://en.wikipedia.org/wiki/Nomadic_empire has a nice list of friendly hunter-gathers and other nomadic tribes that decided to try to conquer their known worlds, genocide their enemies, enslave people, etc...