To be honest, I already wasn't voting for Biden because of his record of mass incarceration, support for the Iraq War, and ghoulish complicity in every major problem the country is facing today. The fact that he's fully and unwaveringly supporting Israel's genocide is entirely on brand and just makes the decision even easier than before. Four years ago, those concerns were the ones liberals were saying you had to hold your nose and look past, now they're not even on the radar anymore and it's moved on to significantly worse things. It's a perfect example of how the democrats move discourse to the right.
The US political system is truly vile in how it effectively brainwashes people into supporting genocide. Even in this thread you can see people defending Israel and saying it's "necessary" for the US to support them, not even sticking to their lesser evilist line but just openly saying it's a good thing for Biden to support them. Once people choose a camp they just end up knee-jerk defending their decision and adopting positions of their candidate to simplify their cognitive dissonance. In some ways, it's worse than a straight up autocracy because of how it manipulates people while still not allowing people any meaningful voice.
Of course the lapdogs of the empire are more than happy to not only adjust their own beliefs into whatever the elites want, but to then browbeat anyone trying to stand against it. Because to them, the positions of our rulers are completely immutable while the moral convictions of voters are up for debate.
What liberals like OP will never understand is that no matter how real the threat of violence towards me is, it will never be enough to convince me to endorse genocide. At least I can go to my grave with a clean conscience, and that's not worth much but it's worth a hell of a lot more than anything Biden would do for me.