The problem is that Hamas did provoke this attack, and while we can debate about 'proportionate' responses, the fact that Hamas (a) uses non-combatants as cover for their military operations, thus bringing death and injury upon the non-combatants, and (b) is putting a political stance (opposition to Israel) way ahead of their obligation as an elected government to look after the well-being of their people makes their actions rather reprehensible, IMHO.
Sorry, but you have the wrong person to be debating such a thing because, I do not endorse the methods employed by HAMAS or their terror campaign against Israel. On the same token, I also find the Israeli military action against defenceless individuals rather reprehensible, and this action should be condemned by all peaceful loving nations. It is rather cowardly to be attacking civilian areas by Helicopter Gunships and then to not expect HAMAS to retaliate by employing any means available to them. One thing is for sure, they do not have the Helicopter Gunships to be able to attack Israel in the same fashion.
Now, Israel is trying to minimize the civilian casualties - 'collateral damage' as the Americans would say - which is in contrast to the indiscriminate rocket attacks of Hamas, so condemning Israel really isn't warranted at this stage... IMHO. Hamas chose to attack Israel, and they chose not to recognize, make peace, or negotiate with Israel. They are now reaping the 'benefits' of that stance, and a lot of people are going to die as a result...
I disagree. Two wrongs do not make a right. Killing over 300 civilians is just not on, and as far as I am concerned this action should be considered a war crime.
If the Israelis were serious about restricting civilian casualties, then they would have sent in the army and conducted house to house searches for the terrorists. This type of action would have been a bit more risky, but killing so many civilians is just insane in my view.