Oh common sense. What has that to do with war? All the training and all the flag waving has one purpose and that is to eliminate any trace of common sense.
I disagree. If a group of people is threatening to kill you (us) because of our values and beliefs, and if negotiating has been proven to be fruitless, then I think we have an obligation to defend ourselves. To me, that is pretty much common sense.
If that group (of bad guys) is using guns and bombs to achieve their objective of killing us (and it IS a stated objective by them), could you suggest an alternate and effective means of defence for us?