nobody's ever argued that sanders is ideal. he's still a lesser evil. and, i've frankly never really taken his bit about corruption seriously - it's just politics.
i've heard elizabeth warren explain away her votes for israeli action by saying something like "america needs an ally in the middle east.". it's the same fundamental policy that's been in place since 1973. it's about the - reasonable - american refusal to accept the saudis as a full ally. it's not about any particular support for israeli policy, and really never has been. it's just all about the geo-political realities around controlling the oil supply.and, the palestinians just get thrown under the bus.
even that said, sanders has taken some really bold positions on the campaign trail. it may not be far enough for most activists, but, even on this issue, it's still incomparably better.
https://www.youtube.com/watch?v=9HdHkdnc7iA
i think that, if you follow the argument properly, the best thing that activists in the united states can do on the palestine issue is support the shift to renewable energy. if we can get off oil, we can get off israel, too. you're bluntly not likely to see positive changes in american policy in the region until the shift to energy independence is completed.