Not the brightest bulbs? Please clarify that statement. This first process of gaining a Ranger contract for a young man joinging the military is a higher GT score than his average peers. The Regiment does not need, nor accept the unintelligent. Not to mention that the other Special Ops units in the Army are largely staffed by men who started their military careers in the Regiment. Young? Absolutely. Dim? No sir.
However, you are 100% correct that there is no possible way that he was fragged by his fellow Platoon members. Nor was he off for a meeting with Chomsky. Tillman and the rest of the Rangers in his Platoon were concered with two things: when would their next hot meal be, and where could they find Hadji and kill him.
Anyone who believes this entire situation was ANYTHING other than a tragic, undesirable side effect of war needs to step away from the cool-aid.