I have had extensive contact with racists, and every single one of them has hated both immigrants and settled minorities; many are in my own extended family, giving me a thorough perspective into their reactions of contempt and consequent dehumanization of outgroups, sometimes going as far as comparing them to insects.
There are cogent arguments for limiting immigration: a rise in the population of first world countries obviously contributes to global warming; emigration hurts the countries of origin by stripping them of talented people. But racist don't give a shit about these arguments because their emotional need to avoid outgroups is always grounded in despicable elitism. Even the economic argument that immigrant-driven population growth takes away jobs, which is wrong but has reasonable elements, is almost always a bullshit cover for their real motivations. Consider the fact that racist governments almost never have a problem with native-driven population growth; most would even like to increase it.
The real upshot of living in a racist society is that the purity spiral never ends. The default attitude of elitism means that there is always someone else that's deemed inferior, someone else that needs to be trampled and made to know their place.