Open borders fantasists always want to turn any discussion of immigration into a question of race, and of course, label their opponents "racists." This is today's trump card: once you play it, your opponent is just supposed to whimper away with his tail between his legs.
For example, one person in my Facebook feed said that Brexit was all about the dislike of "brown people." He apparently is not aware that after 2004, when England was being flooded with very pale Poles, Latvians, and Lithuanians, many people in England saw that as problematic, even though these immigrants were whiter than the average Englishman.
That is because the real issue is culture, not race. If the families of England were to adopt a million Pakistani newborns this year, in 20 years, they would be a million brown-skinned Englishmen. But if 1 million Pakistani adults were to come to England this year, and settle in nearly 100% Pakistani enclaves, then in 20 years, we will see little pockets of Pakistan scattered throughout English territory.
And a culture can withstand some amount of that sort of thing: Catholic Western Europe always had enclaves of Jews scattered throughout its territory, yet remained a cohesive culture. But if you get enough of it, the incoming culture swamps the existing one, which then disappears, or retreats into enclaves of its own. Just ask the Iroquois or Algonquins how their nations are doing today. Or talk with someone from Tibet about Chinese immigration into their country.
And there are people who love their own culture, and don't want to see it disappear and be replaced by a foreign one, whether that foreign culture is embodied in very pale Estonians or very dark Ghanians. The idea that this is all about "race" is a smear propagated by cosmopolitans who don't love any culture.