Correct me if I'm wrong, but Hamas in Syria/Palestinian territories is Shiite, supported by Iran, and is fighting against the Sunni-controlled, US-supported gov't in Lebanon; whereas the Hamas mentioned by COL Lehr is Sunni.
Are the two groups connected in any way other than they both chose the same name?
Also, it's worth noting that there were several extensive terrorist training camps in Iraq, camps whose "students" fought US forces on the March to Baghdad. I had second-hand knowledge of them (I was in country but not in the 101st or 2 ACR). I'm puzzled why their existance and activities have never become part of the war's narrative.