The only thing stupider than European nationalist xenophobia is Americans projecting their own xenophobia over there. I wish people like Mark Steyn fretting about the "demographic decline of the west" were just lone kooks; but I've heard too many otherwise sensible people say things like "Well I'm A Liberal but you have to admit, if the French/English/Dutch start to let all these unassimilated radical Muslims in, how will they preserve their culture and their freedom? It makes you think!"
I wonder how many of them are even aware that France occupied Algeria for 130 years, the Netherlands occupied Indonesia for 300 years, and the English had a bit of an empire thing going on here and there from time to time. This all ended within the lifetime of the current generation's parents and grandparents, and people were going back and forth the whole time. And now people like Steyn think that if non-Christians of North African or Asian descent make up between 4% and 10% of some European countries, and if they're so impudent as to have babies, it's a "fearless Muslim advance" and a cautionary tale for Americans. (And if some nut commits murder in the name of Islam, of course it must mean Those People are uniquely barbaric, because Lord knows the Catholics and the Protestants have always gotten along well over there.) It'd be more sensible if he just said they're after our magic beer.
If you don't want a lot of relatively poor people from another culture to regard your country as a place of opportunity and/or a second home, or if you're offended by their disinclination to assimilate and imitate you, then try not taking over their country. Next thing you know, there'll be Mexicans in Texas and Samoans in San Francisco...