Palestine

By attempting to apply political pressure in this manner, you sway marginal voters away from voting entirely, which results in greater harms than if you did nothing at all. By attempting to apply political pressure, when you're aware that the outcome will be reduced turnout for Democratic candidates, you're making a choice that you're okay with women in the US losing rights to healthcare and reproductive options, and saying that you don't GaF about LGBTQ+ people or any global environmental concerns.

All political choices come with tradeoffs. All actions come with consequences. The consequence here, of getting people to oppose Biden--or just not support him--will be that the speed and intensity of the genocide will increase. Trump favors more and more effective genocide, and Kennedy is a non-starter of a candidate, as is Cornell West (which is a shame, because I like West).

This is the real-life Kobayashi Maru; there is no action you can take that will have the result you want. It's not a moral failing on your part to recognize that this is not something you can control in this way, but it is a moral failing to see the negative consequences of your actions, and choosing to act regardless.