Here's a very instructive thread that starts with the meme that says pretty much the same thing as my "Kittens in the oven" quibcag, which has several versions. Go here [link] if you missed it. The confusion about identity manifesting below has many origins, some benign, some malignant. Yes, in our early years, we welcomed immigrants from Britain and encouraged them to come and become Americans, but such people were our cousins, sometimes quite literally. The basic genetic makeup of an "American" was virtually identical to that of British immigrants. British immigrants did not change our physical or cultural makeup in any perceptible way. To a slightly lesser extent, we were glad to have immigrants from the nations of our cousins' cousins, so to speak, including Scandinavia, all those little German countries, the low countries — Northwestern Europe, in short. Again, there was little genetic difference, and not much cultural difference. The biggest difference was of course linguistic, and even then, these immigrants spoke German, Dutch, Swediish, and other languages which, like English, belong to the Germanic, or Teutonic, language family. This was pretty much the pattern for immigration to America up until the late 19th century, when we started to get somewhat more distant European immigrants, from Italy and Eastern Europe, and also many Ashkenazi Jews., who were much more alien-seeming than the Sephardic Jews who had been in America for quite some time [link]. At this point, it was obvious to many that this was getting a little out of hand, and the Immigration Act of 1924 [link] was passed which was designed to ensure that our basic Northwest European cultural background would not be changed. And, of course, Lyndon Johnson screwed all that up in 1965, as he screwed so many things up.
As I said, this thread from a social media site is very instructive. Achilles, who has the best of intentions, has clearly been thoroughly indoctrinated by the Zeitgeist, and is quite prepared to put butter and jelly on the kitten born in the oven. Only in the last few years, really, has it been considered reasonable to define, say, "Greek" as someone of any race or ethnicity born within the borders of the country called "Greece." Substituting a legalistic definition for common sense is the sort of thing that's popular today, but is no less absurd than it was a century ago. This is all tangled up with the daffy notion that human beings are fungible. Fungible things are equal things, you see, which is why currency is considered fungible, and it doesn't matter which dollar bill you have, you still have a dollar which is the equivalent of every other dollar bill on the planet.
Human beings aren't fungible. Thought experiment. If Iceland, say, decides to take in over the next ten years three hundred thousand Norwegian immigrants — ethnic Norwegians, not the offspring of Somali immgrants to Norway — that will certainly change the character of Iceland, but since Norwegians and Icelanders are genetically and culturally closely related, the changes will be minimal. Now think about the same situation, only with Korean immigrants. Or Kenyan immigrants. Obviously, after ten years, Iceland will be unrecognizable.
Here is the exchange: