I haven't yet seen
Selma, but I know of the fuss raised by two aides to President Johnson (also the custodians to his library?? Why is that a thing). So obviously, they have no potential bias about this. In basic form, the two aides believe that
Selma portrayed President Johnson unfairly (I guess saying that the FBI bugged King, Johnson was more interested in Vietnam than civil rights and the Selma-Montgomery march was King's, not Johnson's, idea-all true, by the by-is unfair now).