'course, when you get right down to it, it's just bald faced xenophobia, dressed up in nationalist rhetoric.
Judaism is alive and well as a minority group in many many parts of the world. "Dilution" has never threatened the existence of Judaism.
The one thing that did was actual genocide, as a result of racism and xenophobia because of fear that the Jews, the minority group, were destroying German culture. Go figure.
But a few immigrants? I think Judaism, or really any culture, is stronger than that.
Another interesting example is indigenous populations in Canada, Australia, and the US. Those cultures have remained strong with the exception of those where active attempts to extinguish them have occurred. The Canadian residential school system is a disgusting, shameful example of the latter.
Frankly, I'd be very interested to see an example where simple "dilution" has actually led to the destruction of a culture. I can't think of one.
If the person you are talking about is such a horrible person, and there are so many horrible people like him in America, why do you want more people to be subjected to them?
I never once claimed folks with these extreme xenophobic views represent any kind of majority in any given nation. They're a vocal, often violent minority. Their voices are getting louder these days, but so it goes with squeaky wheels.
I also never once claimed he was American. In fact, if I had to make a guess, I'd say he's a right wing European. But that's just a guess and isn't terribly relevant.