how on earth does this "logic" (why the inverted commas btw?) effectively allow the attacker to dictate the terms of a battle? i also wasn't aware it was a battle, surely if it was then Israel would have long ago defeated the palestinian army in battle?This "logic" effectively allows the attacker to dictate the terms of the battle. -not really an effective approach if you actually want to defeat the attacking force.
second part of your post depends on your definition of defeat. if you mean defeated as in to wipe them out, kill them all then yea it's not an effective approach. if you want to deter the attacker from further attacks while trying to find more humane ways of bringing about peace then a proportional response to any attack makes sense.