I don't agree with this oversimplified, utilitarian framework you're using. "Lesser Evilism" is a specific philosophical and political framework, and one that is very naive and unexamined.

If a party is willing to screw over Palestinians today, then who will they screw over tomorrow? Trans people? Immigrants? Will you apply the same "lesser evilist" logic as minority groups get dropped off, one-by-one? This is exactly how the ruling class divides and conquers, and so long as that's the state of things, no one's rights could ever be secure.

Standing up for the lives of Palestinians is not only about Palestinians, it is about solidarity. Solidarity is a strategic decision to establish that no one will be abandoned and sold out, that we will not abandon the little guy just for the sake of securing an election. It is only through a foundation of solidarity that we will be able to build a movement that's worth fighting for. To abandon Palestine would also mean abandoning those who are trying to build such a movement, causing it to fracture and streghthening the ruling class.

You can blame me for the ruling class's actions all you want. If the only means I have to stop something they're doing is to fracture the working class and side with a genocidiare, then I simply don't consider that an option that's available to me, and from my perspective, I don't have any means to stop it except by working towards a future where ordinary people can unite with solidarity and take power back.

Suppose I had a suitcase nuke, and I could stop Trump from cutting USAID by setting it off in the middle of DC. Suppose that, when it's all said and done, I'd have saved more lives than I'd taken. If I say that setting off a nuclear weapon in a city full of innocent people is simply not on the table for me, that I refuse to even consider it, does that make me a bad person, a reprehensible monster? Am I responsible for all the people who died from the cuts, because I didn't kill a city full of innocents to stop it? Surely not. But then, if I refuse to support the destruction of Gaza in an effort to stop the cuts, how is that any different? Only from the chauvanistic perspective that their lives are worth less.

Lesser Evilism is a moral framework and a political strategy, but it is not sound or defensible when it's identified as such and examined. But it generally isn't, and is instead presented as "common sense" or "just rational." Really, it's just a rhetorical device used to justify tribalism.