Why do you keep eagerly equating isolation from further migrants, with deportation of already settled citizens by their ethnicity? Why do you assume that everyone who wants one also agrees with the other?
This is why people strawman the pro-migration camp as being "pro-completely open borders" when not all of them claim they are. You can't even contemplate the benefits of a country deciding to bear a little less of the burdens of the world without it being obviously motivated by petty racial aestheticism.