Politics & War.
In our society and system of government the military is subordinate to the civil government. The complaints while understandable do not recognize the military's purpose is to fulfill the political and diplomatic aims of the duly elected government. Yes, you heard me diplomatic aims. The political and diplomatic are at least equal components to victory.
In Iraq our commanders and government had forgotten that point. In Fallujah I our forces were taking the city and doing their job. However, while the military was prepared the political and diplomatic forces were not prepared. The result Fallujah I was a defeat for our forces. However, our government and top commanders learned their lesson (again, real life learning takes hold much quicker than book learning) and all three legs of the triangle were ready for Fallujah II. Fallujah II was a victory for our forces and the Iraqi forces that participated.
In the movie Patton there is a good picture of this. It's the scene where Patton is directing tank traffic and his commander (Omar Bradley) approaches him to notify him they have to divert major amounts of his supplies to take the area where the V1 and V2 rockets were being launched against the UK. Patton was probably correct that allowing the 3rd Army to continue to fight the Germans full strength would have done more to defeat the Germans but the political was at the utmost there.