It's a form of racism that isn't necessarily dislike of people of color, but just... sexually objectifying them because they seem "exotic." A great example would be Avatar (AKA Pocahontas in Space). People thought that the blue people were noble sexy savages, and of course, the white guy totally fucked a blue girl. Sometimes this is also associated with thinking that "primitive" people are somehow more magical. It's all what anthropologists call ethnocentrism - which is really a broader term for racism, sexism, nationalism, etc.
I admit I'm totally guilty of this. I have a hierarchy of hotness in my head:
Indian women - hottest
Middle Eastern and Native American women - extremely hot
Asian women - very hot
Hispanic women - hot
Black women - hot
White women - meh
I admit I'm totally guilty of this. I have a hierarchy of hotness in my head:
Indian women - hottest
Middle Eastern and Native American women - extremely hot
Asian women - very hot
Hispanic women - hot
Black women - hot
White women - meh