If you want an honest answer, it's because for every 1 of the "stop the genocide" people, there's 2 people who support Israel's campaign to bomb Palestine. Mainly because Hamas is often seen as representing the Palestinian people and have done everything in their power to destroy sympathy for Palestinians, and secondarily because US-based advocates for a free Palestine have used methods that seem primarily designed to piss people off like setting up camps in public spaces and accusing random passers-by of partaking in genocide.

Source: https://www.cbsnews.com/news/biden-israel-gaza-poll-cbs-news/ Even after a shift away from Israel, only 37% think the US should even encourage Israel to stop the campaign. To me military aid to Israel makes exactly zero sense. But I also live in reality, and cutting off aid entirely would be political suicide until advocates for it do a better job of actually being convincing.