General George Marshall: "The United States abides by the laws of war. Its Armed Forces, in dealing with all other peoples, are expected to comply with the laws of war, in the spirit and the letter. In waging war, we do not terrorize helpless non-combatants, if it is within our power to avoid so doing. Wanton killing, torture, cruelty, or the working of unusual hardship on enemy prisoners or populations is not justified under any circumstance. Likewise respect for the reign of law, as that term is understood in the United States, is expected to follow the flag wherever it goes...."
It does not matter that Al Qaeda does all of the terrible things that General Marshall enumerated and more. It is not about them. It is about us.