To borrow on some of your words, Black barbers may be related when they come from the same place.
I have a great example where father, son and two brothers-in-law were all barbers, which finally helped me identify the married names of two sisters. I have over 1,000 profiles I manage and I cannot find the profiles to save my life right now, but when I run across their family again, I'd be happy to share the link as a great example of how this is helpful.
In general, my experience is that black genealogy work and white genealogy work in the USA are leagues apart. White people have, especially in the 19th century and earlier, waaaaay more public records, and are way more likely to have benefited from a wealthy white relative somewhere in their ancestry who had the time and money to research and write a whole book on the family history. Whatever we can do to help with bridging that gap seems like a win to me.