To the extent that whites have the power to give/withhold contracts and the like, you are right. However, JJ's real credibility (or lack thereof) as a "black" leader comes from blacks ourselves. If all blacks dealt with JJ the way Rev. Peterson does he wouldn't have a following and would be out there by/for himself. Will more blacks "repudiate" Jackson? Maybe, but most either don't care about him or want him available if they need him to stand up for them if they feel their civil rights are violated.
The real issue, therefore, is not JJ or any other "black leader" but the whole issue of civil rights and how blacks choose to defend them. Most blacks feel that a group strategy at times is needed (right or wrong) to defend civil rights and that's why they are willing to accept "leaders" like JJ and organizations like the NAACP despite their flaws, which are nothing new to the average black person.
(Thanks for the flag)