The Germans started a major european war in the 1870s, and were the first to deploy the Krups Gun against civilian populations many miles behind the lines.. They started BOTh world wars and were the first to use airships for ariel bombing of towns. They had to be stopped. Hitler saw the pacifism and appeasement of the European powers as weakness, and so invaded Poland.
Would it have been any good to say "war is bad and we refuse to fight and kill like the Nazis." Benjamin Britten the composer actually argued that Britain should let the Germans invade, then "set them a good example." !!!!!
Why didnt the US show Japan a good example after Pearl Harbor? As was pointed out, when the US first approached Japan with less punitive conditions of surrender, it was rejected as the Japanese saw this, not as compromise, but weakness, so they refused.
Had America not joined the war, Europe would have fallen under nazi control. They were planning a nuclear bomb themselves, and would have used it. The Germans were already trying to design three stage missiles that could nuke America. (a concept suggested in "Woman on the Moon" 1923)
When your enemy despises your very existence no amount of sweet smiles and concessions will save you.
Sometimes there is NO CHOICE but to fight back with deadly force, unpleasant thought.
And can we have less of the "conspiracy" ideas about the US bandied about by the likes of Noam Chomsky and Gore Vidal. (convincing though they sound)
Setting good examples and special treatment to terrorists in our midst is also seen as weakness, and will sadly lead to even more violence and the need to fight for our survival in the future.