Just War

I'm frustrated by the fact that the current problem in Gaza is so frequently posed as one of "what is Israel supposed to do about the fact that Hamas is shooting rockets at them". I've never experienced living in fear of constant rocket attacks, I'll grant that I don't know how terrifying it might be. Let me also stipulate to the fact that Hamas is nasty and engages in terrorism. But, given all that has gone on in the Middle East, is that really the only question demanding an answer?

More fundamentally, I wonder what has happened over these last few years to our perspective on war and killing. When did we become so blase about the killing of unarmed civilians? (the killing of the unarmed civilians associated with our enemies, at least; we're still pretty good at stirring up righteous indignation when our civilians or those of our allies die) And more fundamentally yet, when did we stop thinking that war and killing is a really terrible thing? I'm not so naive as to suggest that nations should never go to war but I do believe strongly that wars must meet the criteria of just war. And that's not just naivete speaking, without just war, we're just in the jungle practicing "might makes right", no further ahead than wild beasts. But, so far as I can tell, the current attack being carried out by Israel fails the requirements/constraints of just war in at least three ways:
a) It's not proportionate: The force used in the conflict must be proportional to the wrong endured, but that's not true in this case. Palestinians casualties far oustrip Israeli ones.
b) Distinction: The Israeli attack fails the "distinction" criteria, i.e., " Just war conduct should be governed by the principle of distinction. The acts of war should be directed towards enemy combatants, and not towards non-combatants caught in circumstances they did not create".
c) Probability of Success: "Arms may not be used in a futile cause or in a case where disproportionate measures are required to achieve success;" Will Israel emerge from this having their problems solved? If in trying to eradicate Hamas, they manage to get the Palestinians to hate them that much more, will they have ended the threats to their safety? I doubt it.

But what of the fact that Hamas practices terror? They're not a conventional force, doesn't that justify extraordinary means of retribution? This isn' t clear to me. If an agent ends up having to routinely kill women and children in fighting terror, hasn't that agent become a force of terror itself?