I can personally understand why Israel is pissed. There has been no end to the shit everyone in the middle east has been giving them, and in Hamas case they refuse to stop launching rockets. Israel tried a couple cease fires, but Hamas just kept launching rockets. I have even seen Palestinians on the news saying 'this is all happening because Hamas can't keep a ceasefire'. Just because the iron dome is functional doesn't mean that Hamas gets to just keep launching rockets like a group of insane, oversized, petulant children with expertise in rocketry. There are leakers occasionally, and those kill people.
Israel does not have a professional military of sufficient size to deal with this, and as a result most of their forces are conscripts. This leads to idiocy and bad target discrimination. They do not, however, seem to have a choice in the matter as to whether or not to try to use it. They have cut off the outside rocket supplies to Hamas, then Hamas promptly started producing their own rockets. They are producing these rockets with general use materials that cannot be cut off from the country. They literally have to go in and physically prevent the production and or launching of these rockets or they will just keep coming forever.
e: And when it comes down to it, yes, Israel is choosing the lives of their civilians over the lives of civilians in gaza. In my opinion that is entirely reasonable.