You're not from round here, are you?

The EU had a wonderful vision at its heart; peaceful co-existence.    The shorthand for this is 'multiculturalism'.   Everybody would celebrate everyone else's unique features.

But if you repeatedly remind people that they are foreign all you are telling them is that they will never reach the level of acceptance at which the differences are irelevant, unremarked.   It also reminds everybody else that Sanjay, Errol, and Nikita are foreign, even when all three of them have been born here, as were their parents and grandparents. 

It does not matter how well intended one is.  If you point out the differences between people, especially unbidden, all it does is 'other' the person, excluding them by example.  It does not matter how much you celebrate the differences.  That they are different is thereby underlined, even when for all pratical purposes, they are the same as anybody else. 

Thus multiculturalism creates instability.  It magnifies small variations which should be rendered insignificant by time, cutting them like fresh letters in stone:

 "You are not One of Us".