The original question had to be edited down. I would suggest that Hammad's characterization brings to light how the many of those who are considered "terrorists" have complex narratives. Their actions are repugnant. Yet, many of their stories are intricate. DeLillo brings this out with Hammad. His characterization is one that is filled with realities from his past, a complex view of the mission, and a very fragmented condition in which there is no real sense of absolute commitment. Hammad is in stark contrast to Amir, whose has nothing but singular focus. Hammad struggles with the mission and the pleasures of this life. If possible, he could be seen as one who wavers in his full fledged commitment. Even in the closing moments of the mission, Hammad is focused on the water bottle making noise, or the cut on his arm.
DeLillo illuminates the possible construction of the "terrorist's" character. The idea that such a figure responsible for massive destruction is complex is something that he brings out. Hammad is not likable as much as he is intricate, transcending the labels that the "War on Terror" has so easily applied. In characterizing Hammad in such a manner, DeLillo has suggested clearly that the opponent in the "War on Terror" has to be understood and grasped in its full implications. This brings out the idea that the potential path to avoid another day such as that sad one is to engage in a full understanding of those who wish to do harm. In understanding them, a better chance of avoiding bloodshed is possible.