I agree that genocide is horrendous, but you seem to be missing the fact that your alternatives are voting for the candidate that has publicly pressured Israel to stop, and withheld weapons, or voting for the candidate that wants to arrest and deport people that oppose the genocide, and has actively urged it on.
Not voting means you don't care who wins: The candidate trying, at least somewhat, to reduce the scale of the genocide, or the candidate urging for it to increase in scale.
In that case, you are complicit if the latter wins, and the genocide gets worse.
Look: We are loads of people that agree that more can be done. Don't use that as an argument to say that this isn't good. He's doing good things, and if we keep voting in candidates that are more progressive than the previous candidate, we'll see progress. Biden is better than trump, next time let's get someone better than Biden.