She cannot end all relations and support for Israel, it's not possible, practically, or politically. She would lose a far larger voting bloc. She can and will do what Biden and Shapiro have done, call out Bibi and press for restraint. She'll probably be willing to go even a little further. But if that's not enough, and if the people saying they'll sit out the election are serious, they know damn well that it might help get Trump elected, and that he will without hesitation support Israel's complete destruction of Gaza and probably the West Bank too. If that's their position, they never really cared about Gaza civilians, they care more about perception as super righteous self-satisfied progressives. If Palestinian civilians are really that important to them, they absolutely must press Kamala for as much as they can get while voting for her without reservation considering the alternative. That's how politics work, hell it's how life works in general.