If it was just critique, people wouldn’t be genuinely planning not to vote for him, handing Trump the win. It’s textbook cutting off your nose to spite your face.
And if it was just critique (absent any threat of action), then there'd be no pressure for dialogue (which is why leftists regard liberals to be functionally the same as reactionaries, btw). It should be alarming to everyone here if Biden is willing to risk 'handing Trump the win' in order to avoid taking a firm stance against Israel's genocide in Gaza.
People claim they want to work for change, but often prove unwilling to exercise what little power they have to push for it. You're right though; if Biden proves unwilling to concede on issues that are non-negotiable to some of us, then people will be forced to look elsewhere to pressure that change, and what and where that looks like really remains to be seen. So far, two people have self-immolated in protest of the US's involvement in the Palestinian genocide. I think we should all be very concerned about what further actions people will take if the Biden administration continues their unconditional support of Israel, the least of which should be who ends up voting in november.