Let's see...who is likely to support the ADL? I would guess a not negligible part of their support comes from Jews who consider Arabs and/or Muslims to be their enemies, and neocons and Christian conservatives, who also tend to see Arabs and Muslims as their enemies. On the other hand, J-Street is trying to build on the niche of liberal Jews who see themselves as explicitly opposed to Jewish anti-Arab bigotry.
Read the results here and here.
In less depressing (I guess) news about the Jews, or at least if you want to get away from cold rational-choice type logic and read something warm, interpretive, and creative, don't miss Noah Millman on Merchant of Venice. Just an alert -- the first half of the lengthy post, which is a review of the Pacino production, is good, but you don't want to miss the back half of the post.