Or even from urban to rural areas.

> It's just some old timey 1940s "we gotta keep these different cultures separated" nonsense.

That's a huge mistake right there. Those who want to keep their culture should be free to do so, as long as they don't try to force theirs on others - that's a common and traditional American value which is now being attacked by both extremist segregationists and extremist pot-melters.

> It's nationalism and racism (though it purports to be otherwise).

You should learn what these words mean and stop purporting they mean something else.

> It's all made up. Even culture.

Bro, not only culture, the entire human civilization is made up. The issue is to make it good, not bad, but you seem to be all confused about it.