For decades, one of the biggest blind spots of most civil rights "leaders" and "spokesmen" for the black community has been their utter lack of knowledge of economics.
As a purely factual matter, prices do tend to be higher — and the quality of service and products lower — in stores in low-income neighborhoods. But the knee-jerk assumption that this represents "exploitation" or "racism" ignores the economics of the situation.
What he describes can be observed in any other neighborhood. The prices of most products in a convenient store are higher than a supermarket. And usually, the prices of goods in a supermarket are higher than one finds in Costco. It's simply a matter of "bulk" and "turnover" or in other words economics.