If you are generally curious about why this is something that is required, I suggest "Trigger Warning with Killer Mike" on Netflix. Specifically the first episode which deals with Mike trying to get to a concert only using black products and services.

Long story short: The average lifespan of the dollar is approximately 28 days in Asian communities, 19 days in Jewish communities, 17 days in white communities — and just six hours in Black communities. Meaning after that time, that dollar has to go into another community for a product or service.