I think the Dawsey incident being discussed in African Americans Need To Stop Shopping Where They're Disrespected is more about him running into a insolent jerk than anything else - and jerks are in every culture throughout time. The jerk was wrong and any smart businessman would know that behavior is bad for his business and get rid of the employee.

Lowell has a good insight on the incident. On the other hand I think this type of behavior is more common than we realize. My local gas station owner told me that it was ok to fill my tank without paying first while every black patron has to go in and pay first.
As for ownership of the local shops/gas stations I have always wondered why the black community has not invested in their own neighborhoods. Except for a small number of shops the party stores/gas stations are owned by those who have no ties to the area.