I don't see anything wrong with our president standing at the back row, or is there anything wrong with it?

A few people online are criticizing President Jonathan for allowing himself to be placed at the back row of this pic taken at the recently concluded US-Africa summit in D.C. Some say its disrespectful as he is the leader of the 'Giant of Africa'. But some argue that it really doesn't matter as long as he was recognized and invited.

What do you think? Is there really anything wrong with him standing at the back row?