Funny, I have the opposite opinion. I find that dark backgrounds make light-skinned models look a bit pasty and cause dark-skinned models to fade into the background. Whereas light or white backgrounds make models of all complexions look good.
I tend to like the light-colored backgrounds the best, although for me it’s more a question of how much visual information is in the shot than any sense of how the lighting is affecting the model’s skin color. If the background is black, and I can’t see all the contours of the model’s shape because the less lit areas of her figure have disappeared into the shadows, I generally find the photo less interesting. If, however, the fill light in a black-backgrounded set is sufficient to reveal the edges of her form (I am thinking of many wonderful Jasmine Sinclair sets) then I am happy.