White = European, or European descent.
As TD put it, Europe is a very large place. So much of Europe contains people that we once used to call "olive or Mediterranean skinned" meaning white with a nice rub of olive oil and lay in the sun for the afternoon. Very attractive to many people.
The same with Africans. Africa is a large place. You can be an African-American from Egypt or Morocco in the north, Nigeria or Congo in the middle, or have British roots and be from South Africa (and play a lot of golf).
As has been mentioned, with transportation what it is today, people tend to be more homogeneous. Even in my case, grandparents from northern Europe, me here, and I marry a Columbian who has two grandparents from Spain. Her grandmother was whiter than a bed sheet with pitch black hair, not uncommon among Spaniards.
I guess the whole "color" thing may be less of an issue as we all eventually get "tan".