We do not want our countries to be inhabited by a mixed population and therefore we are protecting our borders and oppose migration.
That's plain and straightforward. Why can't more national leaders talk like that?
For us in the U.S.A. of course it's a couple of hundred years too late to complain about having a mixed population; but we can still reasonably ask for our population not to become any more mixed than it currently is. That's not cruel, or hateful, or Nazi: it's just … conservative