Actually I think at least part of his hand over Obama's shoulder is part of his right hand. Compare the shape of the left first finger (over Obama's shoulder" to what's seen of the first finger on the man's right hand. Perhaps part of the thumb was pieced in and maybe that 2nd or 3rd finger on his right hand was cropped on the hand over Obama's shoulder as well.
That sentence is referencing Ann’s black hand.
The bench photo might be his hand from another picture ...