I took a philosophy of biology course (and a separate philosophy of science course too) in university. Which was helpful. A significant portion of the course covered the controversy over whether homosexuality is genetically heritable.
The question of racial preferences is a fair one. It would not be taboo in the sciences or philosophy department. It is unacceptable outside those areas of study because of secular values of right and wrong and what can be asked and what can't be asked.
Any thought or emotion you have is contingent (a term often used in logic department of philosophy) on you having a brain and therefore all these things be they racist or not or a preference for a race or not, can be said to be biologically and genetically dependent. No biological organism or no genes then no emotions and aside from Intelligently Designed A.I., no thoughts.
So, philosophically I would say racial preferences are as biological as homosexuality.
And both are environmentally produced in my opinion. No one makes these philosophical inquires with respects to a thought experiment about a person born blind and deaf. Certainly such a person due to the hormones in their body will eventually become sexually aroused. But over what? And what makes us think sexual arousal requires requires eye sight, sound, and a morphological and phenotypic preference? Nothing but drawing upon are subjective experiences long after our own sexual biases for X, Y, or Z types have been formed.
The ancient Greeks got boys and men to achieve erections over looking at other boys and men the same way cultural transformation in the late 20th century got white American men begin to prefer larger, rounded butt women like Jennifer Lopez over their traditional cultural love affair over large breasted women with smaller, flatter butts.