If you believe that people and cultures are different (which almost everyone outside America believes) then it follows that a region reflects the people who developed it. Countries are, of course, not just land, but they are built of infrastructure, governments, institutions, culture, customs, rules, norms, and values. If Iowa is polite, flat, and egalitarian it’s because Iowans made it that way. By contrast India or China are the way the Indians and Chinese made those places. It stands to reason that if Iowans like Iowa, they might be resistant to immigration from people who are different who will change the place.