I think this is one of the ugliest things about this particular war. While the IDF unquestionably committed various war crimes over the course of the conflict anyway, the bulk of what people found objectionable very well might have been done in total accordance with international law. Despite many failures and excesses, the IDF at least paid lip service to trying to do that, as a policy.
It's just that, the reality is, the rules are based on entirely different assumptions about how war is carried out. If they might lead to something resembling a "humane" war (hah!) when fought between, say, a relatively evenly matched France and Germany, they're quite ineffective at preventing a humanitarian catastrophe when you have a modern force attempting to siege an ultra-dense, militarized enclave run by an organization with no real hope of a conventional victory or interest in the well-being of its civilians.
And so you end up with this absurd situation where the world witnessed, over and over again, unimaginably horrible things being inflicted on the population of Gaza, and the Israelis responding - if we're being charitable, not entirely unreasonably - "Why are you getting mad at us? We're following the rules!"
It's just that, clearly, the rules are insufficient to match people's moral sentiments.