I'm just guessing here, but much of Southern cuisine is often attributed to blacks, in no small part because black women were the cooks on large plantations that ran the cultural life of early America in the South. Fried chicken is very frequently attributed to African cooking patterns. Early American barbecue methods were originally done outdoors in a pit; something that is more likely to have arisen in hot Southern climates and to have had its antecedents in primitive, no-tech African cooking using hot coals and heated stones buried with the meat overnight, or spit roasting over open flames with tree limbs as the only available technology.
Reality is that everybody in the South knows the blacks make the best BBQ. You ain’t from around here are you? :-)
I grew up poor in the South. Only a few years ago I learned that I’d grown up eating “soul” food.