Biden doesn't put that much though into it

He's not thinking through this logically, he's never been logical about Israel:

https://www.motherjones.com/politics/2023/12/how-joe-biden-became-americas-top-israel-hawk/

He's yelled at HW Bush for withholding money to Israel due to their illegal settlements, he's demanded US politicians raise money for AIPAC, over 36 years in the Senate no one took more AIPAC money than him, and he's called for such despicable things during an AIPAC conferencethat it made AIPAC uncomfortable.

Senator Biden used stump-speech techniques, sometimes shouting and sometimes lowering his voice to a whisper to denounce the George Bush-James Baker policy toward the Middle East like an old-fashioned preacher.

Yet even he seemed to admit that everything has changed. One observer described his speech as defensive, brittle and unconvincing-whistling in the dark. And conversations with individual Jewish delegates revealed their uncertainty that the course laid down by AIPAC in support of Israel, regardless of the consequences for American foreign policy or for real peace in the Middle East, was wise or in the long-term interest of either Israel or of American Jews.

One said at dinner, "You know, no one should take Biden seriously here. He is a cheer leader. He helps us, of course, but does opposing the peace talks or ignoring them or disparaging them really make sense? I don't think so." Another remarked how many of her friends at home were divided over the peace talks. They know this is an opportunity that could be lost by the hard-line Shamir approach.

https://www.wrmea.org/1992-june/aipac-s-1992-national-convention-two-views.html

I don't think people realize Biden has been pro genocide for literal decades. He's just so old now that he can't run around screaming about it like he could in the 90s.