They have different skin tones, different complexions, different hair styles, colors (such as “blond” or “brunette”) different lips, eyes, etc. So this whole preference thing collapses with that argument once you actually apply common sense. I always see people say it’s just a preference but I don’t actually hear people say what they don’t like about Black people or Latino people. It’s always “it’s just a preference, I’m not racist.”
I wonder what people don’t like...is it “black” skin?
Except that skin color varies within races just as much as any other trait.
The problem seems to be interpreting this as an absolute. I.e. what I imagine you're hearing is "I prefer trait A, so I'm interested in persons of race X, but none of race Y". But these preferences are rough generalizations, not absolutes. Some traits occur often within certain racial groups, but rarely in others.
Let's take blond hair for example. Imagine a heterosexual man who is strongly affected by blond hair, to such an extent that it shapes whom he is attracted to. The fact of the matter is that blond hair as a commonly occurring trait pretty much only developed in Northern Europe (there are a few other populations it popped up in (e.g. Melanesians), but not at all with the same frequency). Given the priority of blond hair for this man, what most likely will follow is that the women he is attracted to will be overwhelmingly of Northern European descent.
This much I don't believe one can easily make an argument regarding racism. I know some people want to, but there's no clear connection between preferring traits associated with a supposed societal beauty standard and racism, given that people develop preferences for all sorts of traits that don't fit the supposed standard. You would have to be able to read someone's psychological conditioning to be able to make that judgment. And even then, pointing it out on a personal level would be pretty much irrelevant: there's likely nothing that person could do anything about his/her conditioning, and even if there were, there's no obvious reason why he/she should.
The one aspect here that is questionable is whether someone with a preference of traits that predominantly occur within a certain race is justified in expressing those preferences in terms of a racial preference. I would argue that doing so can be a good choice, pragmatically speaking, especially assuming more than one trait being at play. Is there any use in speaking of racism if one states a racial preference for the purpose of weeding out groups that are extremely unlikely to have the traits one is looking for? I see no sense in leveling that criticism. It's simply a convenient tool to specify the pool of individuals who are more likely to have the traits one is looking for.
