I think you miss my point entirely. Collective punishment and a war of attrition are two very different things, albeit they may look similar from a distance.
The war of attrition is simply exhausting your enemy's capacity to wage a war or resist your own war effort. It is morally neutral in the sense that it does not try to distinguish "good" enemies (i.e those who surrender) from the "bad" ones (i.e. those who keep fighting) and punish the latter - it simply drains the enemy's resources that can be used in waging a war.
A collective punishment is "moral" in the sense of making the aforementioned distinction and to apply punishment accordingly. However, it differs from Western jurisprudence in that it recognizes that individual acts and guilt do not reside in individuals, or at least individuals alone, but in social groups and collectivities that shape individuals. An individual alone is but a feral child, an animal if you will, if it survives at all. It is society that provides him/her with all necessary material, emotional and cultural resources that constitute him as an adult human being. Believing that individuals can achieve that on their own is the biggest lie and self-deception of the US way of thinking.
If collectivity is what ultimately constitutes an adult individual -his/her mindset, values, goals, acceptable means of their achievements etc. - it thus follows that collectivity is also responsible, to a point, for the action individuals take based on these mindsets, values, expectations etc. It further follows that such collectivities can be culpable and thus subject to punishment.
Again, this is a philosophical speculation on "what if" we abandon the silly notion of individualism what permeates the US way of thinking. It does not advocate or exonerate method of collective punishment.
I would also add that our revulsion to or acceptance of killing others rests entirely on with whom we want and are willing to empathize. We abhor killing of creatures (people or animals) with whom we empathize - but take away that empathy and killing is nothing more than swatting a fly. Since empathy can easily be manipulated, the main propaganda effort strives to reduce empathy for foes and increate that for the enemies.
Wojtek