A lot of black businesses I go to are indeed well managed and run professionally. But yes a lot of them in the hood particularly (NOT ALL) are disorganized and give poor service especially when other blacks come in.
Multiple times I've been to smoke shops, weed spots, convenience stores, beauty supplies, and restaurants owned by black folks who will stare you down when you walk in, not look up from their phones to greet/acknowledge you, and sell an inferior product at a premium price. Everything is a mess, the racks are dirty and disorganized, and the merchandise is all over the place. I've also been in them and watched whites get the red carpet rolled out for them while blacks get stank attitudes and slow service. At Roscoe's Chicken and Waffles which is an otherwise well-run black owned establishment, the dude walked up to the table and said "what chall nikkas want?" Like seriously?
Now...to be perfectly fair I've had similar experience at Arab, Korean, Latino and other non-black stores and would rather patronize the black ones than the racist Arab ones. But I feel what OP is saying and think that those particular black businesses that half ass things should step it up. And we have to get out of the habit of giving up crappy service to blacks, to me that's just self-hate bubbling up to the surface where you think people who look like you don't deserve exemplary service.
A model black business for a professional operation that is well-run and handles their business is Eso Won Books in Los Angeles.