Just remember all the American support the 2nd Iraq war started at only for that to collapse as people realized the Bush administration was loaded with war criminals.
It's a little different because as far as Israel is concerned, this war is normal. It's an extension of the status quo that Israel as a country and a people has already accepted since 1949 and never changed it since, not when they elected Netanyahu in 1996, not when they kept reelecting him for 20 years. And support for the right wing is rising, not falling. That's different in America because in America a war in the Middle East is not the status quo. If you wanna compare compare to Native Americans and European settlers.
What I'm trying to say is: If we wait for Israelis to realize that genocide is bad on their own, the best we'll get is some crocodile tears and an apology from their Lebensraum to what few Palestinians remain after they successfully genocide them. Don't expect much from the Israeli public on that front; these people want their Zion.