I think that Breitbart had the tape since the March speech, and was just holding it, then when the NAACP decided to do their resolution that the Tea Party is a racist movement, he released it to show that NAACP (not Sherrod) was a racist movement.
"Have we overcome? One man's memories of the Civil Rights Era." by John Chappell
It talks about Shirley's husband, Charles who was a real activist...but not a bad person back then.
Right after they got married, their house was burned down. And I have a feeling Charles' activities might have caused her father's death and that is why she doesn't pursue "justice".
I believe they started out with good intentions but like many causes, were swayed into the reparations game. Yeh, as usual, it's all about money.