There's been a lot of talk about what constitutes a proportional response to Hamas rockets landing in Israel. Proportional smortional. It isn't about proportional responses, its about effective responses.
And in that vein I ask, what if Israel had not responded militarily? What if they had taken the protest route at the UN, in the press etc.? What if they had taken the high road? Conceptually it could have boasted Mahmoud Abbas's credibility as a broker that Israel is willing to talk to, and in turn discredited Hamas as a voice of Palestinians. Western opinion would be solidly behind Israel and Hamas would find itself increasingly isolated. This is waht would be considered a constructive solution.
Right now, because of Israeli aggression in Gaza, Hamas is on the rise. Abbas is being attacked as ineffective, weakening his authority. So how does Israel win this engagement?
Isreal is attempting a destructive solution. To win they have to utterly destroy Hamas as an effective organization in the Gaza Strip. (But Hamas is also in Lebanon, the West Bank, Syria etc.) With military might that means eradicating all Palestinians from Gaza and reclaiming it as Israeli territory. They cannot leave any significant number or Palestinians behind or Hamas will move right back in. When Israel pulls out, and Gaza still exists as a Palestinian territory, they lose. Hamas may be damaged, but there will be plenty of recruits willing to step in where others have fallen. The only net result from this engagement will be the loss of innocent life, the destruction of whatever state infrastructure that existed (IE bomb them back to the stone age), and the radicalization of many of the survivors.
Two years (or less) from now? Rockets will rain down on Israel from Gaza again, if not from the West Bank too.
Not only would world opinion universally condemn Israel if they tried to commit genocide in Gaza, logically its infeasible as well. The state sanctioned murder of 1.5 million people is not a simple exercise.
If this all sounds cold-blooded and unfeeling, its only because this is the logical end game for the current Isreali military initiative. They're murdering people to no effect right now no matter how you look at it. If these deaths are going to have any meaning beyond perpetuating the status quo, than victory has to be assured.