At university I had two friends who had very specific racial preferences in the opposite sex.
Friend #1 was a white male who only ever copped off or had relationships with women of Far-Eastern descent. Friend #2 was a white female who only ever went out with black men. Neither of them openly said "I will only go for this or that ethnic minority" but in practice it was exclusively so.
Is this #problematic? I can't make a coherent argument for it being so, and yet people seem somewhat obliquely uncomfortable with it.
Incidentally (or not?), they both subsequently married white partners many years later.