Because that arbitrary region is your home, it and the people in it provide the resources and structures you need to survive. Human "weirdness" is the end product of millennia of natural selection, it's the result of optimizing for survival and success. Think on that before you rush to tear down Chesterton's Fence
Are they? Humans aren't interchangeable atomic GDP-increasing machines, people from different places have different values, languages, and culture. So someone from "over there" might not fit neatly into the structures we have "over here," and vice versa.
