The situation is beyond horrible, and sadly, the only thing we can be sure of at this point is that there is much more killing, pain, and suffering to come.
The attack by Hamas was a brutal, barbarous, terrorist atrocity - that deliberately and systematically targeted innocent civilians. Anyone defending it, or cheering for it, or excusing it, or in any way whatsoever trying to justify it needs to take a long hard look in the mirror. Whatever the cause, and whatever the anger, and whatever the provocation, the only correct response to the slaughter that Hamas brought to Israel is outright condemnation.
However, this does not give the Israeli government the right, via its military, to indiscriminately starve, dehydrate, and slaughter innocent Palestinian civilians in retaliation. This is termed as 'collective punishment' and is illegal under international law. Moreover, it won't work either, Hamas can no more be militarily 'defeated' than the IRA could be 'defeated', the solution to this seemingly intractable problem, if it ever comes, will be via a political agreement, it will not be reached down the barrel of a gun. (See also, the IRA in the UK, or The Taliban in Afghanistan for that matter, which had the US military complex up against it, and yet was ready to assume power the second the US left, having never even remotely gone away or been 'defeated' in the first place.)
As had already been noted above, Hamas doesn't care about Palestinian civilians, it does, and will continue to, use them as human shields. If Israel decides on a ground offensive into the Gaza Strip, what will follow is slaughter on a massive scale, with huge loss of life on both sides.
There's a lot of history with the situation in and around Israel, if you're after a decent explainer, (because context really is important here), I'd recommend this video made by Rory Stewart in the last few days, which gives a decent potted history of the region. (I think Rory Stewart is probably one of the best political minds the UK has.)
The only way this ever ends is the two-state solution being implemented, if there is indeed another war in the region (and Israel have already declared themselves to be at war), it will be the third in a hundred years, and it will no more resolve the situation than the previous two did.