Why are the uncommitted SUPERDELEGATES dragging their out their vote to the advantage Senator McCain ?

If they are affiliated with a state that has already voted I don't see why they would wait. I can see why the party heads are pushing for a decision right after the end of the primaries in June. Anyone that would wait until the August convention certainly would not be concerned aobut thier party and they are supposed to be the cream of the crop in the Democrats.