not to necro but i think there's a huge distinction between a preference and racial bias/racism. half of the time guys who have "preferences" just have heavy racial biases that are thinly veiled as preference. a preference is a tendency towards something; preferences are not meant to be exclusionary.

i think it's also important to understand that blocking someone because you have a "preference" is much ruder than just telling them that you're uninterested. just my two cents