You make a good point, and I do agree that diversity in locations can be pretty cool, but the argument falls apart without further modification when factoring in people like me, who are mixed race and multicultural in a mixed and multicultural society. I'm fine if people want to be separated in their own countries, but I do not like being separated in my own simply because I have so many influences from so many different cultures. The closest thing to a culture I have is internet culture, and a few other subcultures on the internet, but those aren't tied to any location other than Earth, so don't work very well with nationalism.