He always supported Israel... I think the 'until' is in reference to Israel's more recent and more blatant attack on Gaza - prior to that, Biden's support for Israel wasn't nearly as flagrant as it is now.
Like, no one would bat an eye if I told them I support my wife's decisions, but if she started breaking into the local NICUs and stomping on people's babies, my continued support for her decisions would be a tad sus. ...especially if I regularly said "honey could you tone the baby-stomping down a bit?" as I handed her a new pair of baby-stomping boots.
I'm not a both-sides'er (unless I'm talking to a trumpanzee in an attempt to steer votes away from Agent Orange). My vote is going to Biden and I encourage anyone reading this to do the same, but our complicity in the genocide on Gaza is genuinely upsetting, partly because it's complicity in a fucking genocide, and partly because this WILL cause voter disengagement and could hand that other dipshit the presidency on a silver platter.