I read the article this morning before work, and I had a lot of thoughts about it...
I certainly didn't expect the majority of blacks I met at my college to be West Indian, African, or Central American. At a pre-Orientation seminar for students of color, I was one of the rare ones who could say that both sets of grandparents were born in the States.
But then...in my close circle of friends, there are only a handful of us who can say the same thing---regardless of race. In fact, I'm sometimes seen as the "All-American" girl

just because when I go home, it's to Florida and not Yerevan or Colombo...I didn't grow up speaking another language, or eating the cuisine of another country.
I wouldn't be surprised either to see that the majority of "American" blacks at the elite colleges are affluent. I suspect that middle- and working-class black students are either going to their state schools (if you look at the incentives they are giving, a savvy student can literally get PAID to go to a state school), an HBCU, or to a school that has amazing financial aid opportunities, like Princeton (no loans as part of its student aid package) or schools that give large minority scholarships.