I had to retract my point about Hank Thomas and bitterness. Better informed voices prevailed.
I think it's easy to read too much into this sort of thing because a lot of us hip-hop era black folks perceive a kind of bitterness in our parents or grandparents. This deserves qualification, almost to the point that maybe bitterness isn't the right word. It's easy to sing "We are the world" when you really haven't seen much actual, real-time racism--and violent racism at that.
At any rate, I think Chris Rock's "cracker-ass-cracker" piece, with humor, gets it about right. As an aside, please avoid overly literal deconstruction of jokes. ("There were no black people who functioned as actual cabs! How can he say that?") Whenever we're talking stand-up, someone decides it's time to talk physics. It's a joke. Let it be.