Yes, it is still objectively right. Anyone deciding not to vote for Biden isn't automatically culpable for any Trump victory unless they voted for him personally.
Again, Biden has had plenty of time to prove that he's against genocide. To take any sort of major action to try and stop this genocide from continuing the way that it has. Or at the very least taking away all US military funding from Israel. He has done none of that while approving additional military funding for Israel.
This is of course before bringing up the electoral college and how the majority of states don't even get a say in the presidential election outside of their states predetermined answer.
I will not vote for anyone funding genocide. Again, if Trump wins that's entirely on Biden and the Democrats for failing to do anything. The signs have been here for months if not years in terms of voter disatisfaction: and they continue to do fuck all.