Sorry OP but what you're saying is absolutely insane, to think in any way killing innocent human beings is acceptable is quite frankly disgusting. You should be ashamed of yourself for trying to justify such a thing.
99% of people don't want war as no one wins, remember the easiest way to create a 'terrorist' (aka enemy) is to kill his father, his sons and take away everything he once knew until he gives no fucks.
It's all fine sitting on our sofas 5,000 miles away from real conflict speculating about killing civilians, but please take a walk in a Palestinians shoes and watch the world around you crumble, watch your friends and family being slaughtered then come back and ask the same question.