"This sounds extremely doubtful."
Yes, it does, but I did hear similar grumblings about another pro-life photo op. I really can't remember clearly what it was, and I may have it all mixed up. Suffice it to say if this is accurate it is mere stupidity above all else.
It's just possible that some staffer lined up the pro-lifers according to rank or importance or some such, and the few black people there got pushed aside, but it's very hard to believe. Certainly Bush leans over backwards to be polite to black organizations, even though they regularly bash him for it.
I don't remember the name of the great lady who first organized the annual marches on Washington, but I believe that she was black. And widely praised and admired for her good work.