Uh, what? We are in the same tribe. That's what being a citizen of a country is supposed to be about. We're all paying into the same government, through sales or income taxes they tend to take a similar bite whatever the income level. Even if you regard local solidarity as mere sentimentalism, there are very pragmatic reasons for me to be concerned about the welfare of my neighbors -- crime, public health, and so on.

I live in San Francisco. When the big earthquake hits and someone has to pull me out of the rubble, they won't be outsourcing that job to the Philippines. It'll be some guy who lives near me, probably the kind of guy with a broad back and an unironic mustache, who has to make do with underemployment since all the local jobs seem to be for douchebags with iPhones.