Didn't know Tim Kaine also boycotted. Gillibrand, Booker, Schumer etc are all in the pockets of donors, a large portion of whom are Jewish. You also have to account for the fact that NY has a large jewish population.
NY jews are liberals who support a two state solution. This "in the pocket of jewish donors and voters" is stupid.
This resolution was pro-2 state solution though. So why didn't they back it?
The fact is, American Zionist Jews are pro-2 state solution in theory only. They don't advocate any policy that will actually lead to it happening in practice. Anyone who is legitimately pro-2 state solution should be extremely hard line against settlements. Settlements are an attempt to force Israel to annex the West Bank.