Your standards of beauty and attraction are at least in part ingrained into you by society. If you live in a racially unequal society then some of that passes on into your own attitudes. This is call "internalized prejudice", and it's why some women among the more conservative areas of the US, believe that their sexs role is truly as domestic caretakers.
It seems to me in the gay community "it's just the preference" is the dating equivalent of "some of my best friends are black". The idea of preference being innate instead of conditioned tries to remove personal responsibility from what is conscious decision making, i.e. it's just how it is and there's nothing they can do to change it, and thus they don't need to. And, since you can't be born racist, and that they believe they were just born like this, they can't actually be racist themselves.
There's also the varying levels of racism that's all thrown under the same umbrella of "racist". There's the overt kind, where white people are burning down black churches calling blacks the n-word. But there's also the subtle, insidious kind, where prospective employees with "untraditional" names get passed over for "normal" (read: white christian) names. Where teenagers enthusiastically engage with music from black artists but remain cloistered in their all-white (or all-asian as the case may be across the pond) social bubbles. When people hear "racist", they think of the former. The hate crimes, the trolling, the antagonism.
But I would argue that it's the latter that contributes most to oppression of minorities. No one robs you of opportunity when they yell a slur at your face. It's a moment of sadness and anger that disappears with the next day. It's the systematic prejudice that's really damaging. Children being shunted off to poorer schools, actors missing out on bigger roles, gentrification and white flight. All these things are the real obstacles to creating a multi-cultural society because they suppress the rate of change.
And I see the Grindr phenomenon as just part of that. I don't think it's coincidence blacks are so undesirable among both the gay and the straight dating scene, and that will never change if people just hide behind their "preferences" rather than engage in honest introspection. Because those preferences get passed on. They didn't come from nowhere, and they don't stop at yourself. It's a pattern that keeps repeating as long as you're contributing to it.
