Why are some people attracted to people of other races? Is it true that we were evolved to dislike people of other races genetically?
If so, why are some people attracted to people of races other than their own?
This is in reply to your first question.

Taste – in food, music, and sex – is in part a result of imprinting. You find women or men attractive that are like your parents or the community you grew up in because of sexual imprinting (e.g. Aronsson, 2011).

Aronsson writes of a sensitive period where this imprinting happens, but I am not so sure that the development of aesthetic taste is actually limited to certain phases in a child's development. Caton et al. (2014) showed that children can acquire the taste for "greens" if they are repeatedly exposed to the food (e.g. having to eat one spoon every time spinach is served). And tobacco, beer, and coffee are prime examples for voluntarily "acquired tastes" later in life. Nevertheless, even an acquired taste is a result of exposure and habituation. Coffee, beer and tobacco are not "exotic" in our culture.

Bem (1996) posited the theory that adults find erotic what was exotic in their early childhood. Thus, a girl that felt different from other girls in childhood would become a lesbian, being attracted to what she was not. This theory has been refuted (e.g. Peplau et al., 1998) on the grounds that it was not supported by empirical evidence.

I could not find anything more substantial in psychological research during a cursory search. What I found are books and articles in cultural theory that look at the popularity of exotic women in the media (e.g. Mendible, 2010). Scanning the contents of those books, I thought that maybe men who are attracted to exotic women are not only attracted to their physical appearance, but also to what these women represent. Thus, Latin women may signify lust for life, African men might stand for physical prowess, Asian women might signify servility, or Oriental women might siginify sophistication and mystery. I'm just quoting some common stereotpyes here as examples for how attraction happens not only on the visual level but also in what we project into the person we desire. Men who like women with glasses might not find them visually beautiful, but might be attracted to the idea of an intelligent or "bookish" and shy person, and this fantasy and eroticsim will even hold despite a contradicting personality.

What I want to suggest with this is that reasons for some kinds of attractions might not be systematic (i.e. the same for a large enought group of persons to discover this connection through empirical studies) but widely different between individuals: one white man loving black women might love them for reasons completely unlike those of any other white man loving black women.

But maybe someone else has the time for a more thorough search and will find a study on this subject.



Sources:


Aronsson, H. (2011). On Sexual Imprinting in Humans. Available online at http://www.diva-portal.org/smash/get/diva2:415143/FULLTEXT01.pdf
Bem, D. J. (1996). Exotic becomes erotic: A developmental theory of sexual orientation. Psychological Review, 103(2), 320. Available online at https://labs.psych.ucsb.edu/roney/james/other%20pdf%20readings/Bem%25201996%2520Exotic%2520becomes%2520erotic.pdf
Caton, S. J., Blundell, P., Ahern, S. M., Nekitsing, C., Olsen, A., Møller, P., ... &amp; Hetherington, M. M. (2014). Learning to Eat Vegetables in Early Life: The Role of Timing, Age and Individual Eating Traits. PloS one, 9(5), e97609. Available online at http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0097609
Mendible, M. (Ed.). (2010). From bananas to buttocks: The Latina body in popular film and culture. University of texas Press.
Peplau, L. A., Garnets, L. D., Spalding, L. R., Conley, T. D., &amp; Veniegas, R. C. (1998). A critique of Bem's" Exotic Becomes Erotic" theory of sexual orientation. Available online at http://folk.uio.no/thomas/gnd/critique-of-ebe-theory.pdf