I think it's less the impunity and more the active supporting. The US is building a floating pier and air-dropping aid instead of simply pressuring Israel's government to let trucks through.
No, they do not. There are still less full aid trucks even after the murder of the World kitchen volunteers massively increased international pressure on Israel to let aid in.
Northern Gaza is now in full blown famine as defined by top US officials that define famine, with southern Gaza on the brink of famine, as all farming infastructure inside gaza gas has now been destroyed. They need drastically more full trucks than the the 500/day that was the norm before the war started, not drastically fewer.
https://www.timesofisrael.com/un-aid-coordinator-says-israel...