Not a fan of the liberal conflation of racism with a predisposition for racial discrimination in this thread; there is a difference between the two.
Racism is about superiority, and is not mutually inclusive with having a predisposition for racial discrimination that would govern and inform a person's physiological responses, such as sexual attraction.
There is a wide gamut of variables that regulate sexual attraction and stimulation (many of them operating at a subconscious level) and most of them have nothing to do with whether the subject of interest has a penis or a vagina! Many of them have to do with physical features and attributes, such as body frame, height, skin elasticity, eye size, facial structure, vocal tone and timbre, body odor, and as you might have guessed, eye/hair/SKIN color, among many other things. The significance and weight that each feature carries in terms of influencing sexual attraction will vary from person to person, but they are important factors nonetheless.
It's important to make the distinction between racism and racial discrimination because one comes from social constructs (which are malleable), while the other (in the context in sexual attraction) comes from genetic/environmental predispositions (which are immutable). If someone isn't sexually attracted to Asian people, it doesn't mean that this person finds this race of people to be inferior to other races (which would be racism), but that he/she simply doesn't have a physiological response of sexual stimulation when he/she encounters an Asian person, due to the defining features that make them Asian inherently taking the place of features that would otherwise sexually stimulate him/her.
Is it discrimination based on race? Absolutely, but it's about as wrong as a heterosexual person discriminating against their own sex when choosing who they want to fuck. In other words, it's natural, and perfectly normal and acceptable.