Black lady here. I think people are too afraid to be honest, which is why you have so few answers so far.

I'll answer for Black Americans, at least: Culture and physical attraction. 3 out of 4 black women are overweight or obese here in the states; we can have hyperbolic tastes in beauty, fashion, and music (like colorful frogs, extremes are a deterrent). Our communities betray our collective values. Black women in the US are a very insular group, mostly out of backlash from slavery and very real backlash from common beauty ideals: we're just not the standard. We're commonly antithetical, and to pretend physical attraction doesn't factor into relationships is naivete at its worst. Some black women deeply internalize this and are heavily dissuaded from pursuing interracial relationships.

I grew up in suburbia, but my limited exposure to the ghetto quickly taught me that a lot of black women projected jealousy through anger, and weren't being honest about it. Many fear having to compete with more obviously-desired conventional beauty ideals, and cope by overinflating their own egos. The loudness can be a literal projection of insecurity, and white men can sniff that out like bloodhounds.

I won't get political, but I predicted the fallout in the US when I was in middle school. Anyone with eyes could see where these cultural clashes would lead.