Because the implication here is that she thinks having sex with black men is more degrading/humiliating and getting beat up by them is like, more "savage" or something than other races
My liberal friends all disagree with me and thinks I'm kinkshaming, being racist myself, or invalidating her "preferences" or something (which I think is usually also racist, having racial preferences unless there's some shared culture/experiences)
If she just liked to be gangbanged and beaten up, that would be a kink, but making it a racial thing is definitely racism. Pretty sure even if it was a black woman the most it would be is internalised racism.