It's not serious to suggest that Israel did not supply any food or water to the Palestinians when in fact it supplied plenty. Why didn't Egypt supply food and water to the Palestinians? (Before Israel took the border corridor).
What other war can you provide me as an example where a the opposing side provided supplies to its enemy? Does Russia supply Ukraine with food and water? Does Ukraine supply Russia? Did the allies supply the citizens of the Islamic State with food and water? Yes- The Gazans depended on Israel in many ways before they started this war, most of them by their own choice. Did the Germans deliver food and water to the UK during WW-II? Do the Turkish give the Kurds food and water as they bomb them? If the government of Gaza, Hamas, has stocks of food and water, and it does not disburse those to the population, and even steals aid from the population, why is this Israel's problem?
Those organizations you're referring to are anti-Israeli and their statements are political.
The US, who has closer knowledge of what's going on on the ground, says Israel has not committed war crimes.