Like a lot of people here, they don't really consider Palestinians worthy of human rights. It's no surprise they want them to starve in a desert. Just a total albatross of an "ally" who provide nothing but headaches.
And when the hell did "other awful nations did it too" become an excuse? Last I checked, regardless if you supported the wars or not, the United States at least tried to build semi-functioning nation-states in Iraq/Afghanistan. They never starved the civilians. Only nations partaking in genocide go that far.
Find me an example of the US going out of its way to deliver aid to a country or entity it was actively at war against at the moment.
Israel's conduct in this war is standard, if not exemplary. The reason for its treatment is because its very existence and acts of self-defense are considered a casus belli by its enemies.