Underlying attraction starts and ends with black women. Most dudes aren't checking for the average boy bodied Asian. She needs black features to be "special". Same with white girls.
I'm not sure about the thighs.
Anyway what is your point?
The only advantage is the way they treat their men but that's because they have a better culture and model than the average african American woman has. And judging by a post above black men treat them no better than they treat any other race so the special treatment is culturally ingrained and not something the guy is deserving of.