There are segments of the population -- both of which I probably overstate the importance of, given their over-representation amongst the commenteriat -- who really view situations like the Gaza conflict as simple, cut-and-dry. Either Israel, responding to illegitimate aggression by Hamas, can respond with whatever force it wants, for however long it wants. Or, Israel, being essentially an illegitimate occupying power, cannot respond to any attacks on it by Palestinian terrorists, and accordingly any response is assumed, facially, to be immoral and probably criminal.
Both of these positions are, it should be needless to say, wrong. Israel has a right to respond to terrorist rocket fire, and its response has to be within the bounds of the laws of war.
But what does that entail?
One of the frustrating things about this conflict is that a serious moral evaluation of it required very local and specialized knowledge that few, if any, of the commentators had (and that's true in both directions). The Palestinian death toll for this operation was a little over 1,000 people, with roughly half of those being civilians. This is being decried as far too many. Well, in one sense, that's obviously true -- any amount of death is too many, because our default assumption should always be that people should not have to live in war zones. But within the context of a large-scale counter-insurgency operation in a heavily urbanized area against a foe which uses civilian shields, how does 1,000 dead stack up? I have no idea.
What are the proper rules of engagement for conducting urban counter-insurgency? How does one respond to the large-scale use of human shields, or the more general embedding of military personnel and equipment in civilian areas? These are difficult questions, both from a moral (just war) and technical (military tactics) standpoint. I know the IDF does actually do a lot of work developing rules on both ends of the question. But it is fair to say that the IDF is somewhat of a partisan player in this discussion, and that particularly from the moral side of things it might not be quite right to devolve the rules over to them.
An area I think that could use a good dose of heavy-duty progressive thought is the arena of moral conduction of military counter-insurgency operations -- from large-scale strategic considerations to smaller-scale tactical rules of engagement questions. Without those baseline metrics for evaluation, we really have no way of really warranting a lot of the claims many are making about the justness of Israel's military response on a micro-level. It's precisely that gap, I think, that drives many to the extreme -- they really want to judge Israel (innocent or guilty), a sound judgment would rely heavily on micro-level questions we can't answer (both because the empirical data isn't available and because the metrics by which a judgment could be made haven't been evaluated yet), so we push the debate to the edge of the cliff where those questions fade into the brush in favor of more macro conceptions of who is "right", overall, in the contest.