Aw, man, you caught me! That's my problem. I'm ignorant. My bad. Lemme go get some education.

Whether or not you can choose it, you are making a judgment about an entire class of people based on their skin tone.

A Jewish person might decide for religious reasons that he only wants to date other Jewish people. He may have a very good reason for this, for instance he wants to raise his children in the Jewish tradition or he wants to have a Jewish wedding or whatever. It's still discriminatory.

In ways, dating is about discrimination. Yes, you're nose-ist, and I'm age-ist.

people can't choose what they are attracted to

Can you back that up? Moreover, just because you don't think you've made a conscious decision, doesn't mean that a decision hasn't been made - a choice that you weren't born with, already formed in your consciousness.

I don't pretend to be an expert on sexual fetishes or what causes them but I suspect it is a multifold scenario with many variables and that many people have different "causes" or what-have-you behind their fetishes. I would posit that is far too broad a subject and one in which I have too little knowledge for me to comment on.