Regarding black culture and southern culture, I think to a large degree black culture is southern culture and vice versa.
Example: Here if I get a craving for fried catfish or smothered pork chops or collard greens or other such folk fare, I can think of several restaurants that offer it (though not nearly as many as there used to be- sigh- frigging chain places). If I were in New York City or Chicago (which admittedly was founded by a black guy but he was Haitian so that doesn’t really count) or San Francisco and I got a craving for those foods the best bet would be to look under “soul food” in the yellow pages. If I were in Detroit or D.C. I’d probably find several places. What’s called soul food outside the south is just called ‘down home food’ in the south.
Black southerners started (weren’t the only contributors to by any means, but definitely were the founders of) the Blues, R&B, gospel, rock, and occupy spaces in the ancestry of country and alternative.
African Americans are a bit like the Jews (no Sammy Davis Jr. reference intended) in that they take their culture with them. The Scots-Irish and English and Irish-Irish and Scots-Scots (kind of like saying chicken-fried-chicken but a distinction nonetheless) influenced the traditions and clannishness (note the C, not the K of that spelling) of Southern society but mostly they assimilated into an amalgam. Certainly not all white southerners are homogeneous, but there are some values and attitudes that are found in most Venn Diagrams of southern cliques, black and white, and identity as southern trumps and for centuries has trumped European identities.
A difference comes when white people leave the south. Within a generation their kids were usually “Yankees” or “Midwesterners” or Californians or whatever with notions of where their roots are generally lost altogether. Diogenes is from Louisiana IIRC but his kids probably have no identity as southerners. I’m always amazed however at how many black families- especially those in Detroit and the northern metropolises- keep close ties to the south. In most white families I know the kids will know their grandparents and visit them occasionally after leaving the region, but the cousins and aunts and uncles are people you get Christmas cards from if that, whereas I know several black southerners whose family members split off in the 1930s and 1940s for the north and their descendants still know each other! (I’m amazed at this- in my family if you move 40 miles away you’re spoken of as if you died in 1958.)
So much of black culture really does stem from the South even among some families that left here generations ago. I’ve no doubt there are exceptions- I’ve known black “valley girl” and “surfer dude” types for example- but to a large degree they carried the south with them when they left.
On an unrelated topic, a book recommend:* Journey Toward Justice: Juliette Hampton Morgan and the Montgomery Bus Boycott *by Mary Stanton. Juliette Morganwas a white patrician southerner (a descendant of Wade Hampton, whose immediate family owned more than 4,000 slaves at the outbreak of the Civil War) who became a librarian in Montgomery and was one of the most outspoken white supporters of the Civil Rights movement. She lacked the money of some of the famous white liberals (Henrietta Maguire for example) or the political protection of people like Clifford and Virginia Durr, so she had to bear the full backlash of supporting Rosa Parks and MLK, and that backlash was swift and brutal. It’s a fascinating read that does much to answer the questions of why people who knew the Civil Rights movement was right still didn’t speak out for it, and while you praise Morgan (who wasn’t an angel and had some baggage) you have to seriously wonder if you’d have been that brave.