(1) There are issues besides Israel; Democrats tend to be much better on economic issues that concern the community.
(2) Obama’s policies towards Israel are pretty much the same as GWB. If you don’t believe me, read the “Road Map” of the latter where he uses the term “End the Occupation” and endorses the Saudi peace plan that includes the 1967 borders. It also included a settlement freeze! Most Republican apologists have not read the Road Map. The major difference between Obama’s and GWB’s policies are that US-Israel military cooperation is now at its highest level in history.
(3) Most Democrats and Republicans in Congress are pro-Israel; there are few on each side of the aisle who aren’t.
(4) The number of really crazy nutty Republicans running this year greatly outnumbers the really crazy nutty Democrats.