In some ways it's similar to Kabbalah, but that isn't a big part of mainstream Judaism today. Judaism as we practice it is so rationalistic. But that's just a partial view. The popularity of Buddhism among Jews could also be a reflection of the times. People are so cynical about the possibilities for group progress.
People are more interested in their own salvation rather than producing a just society.
I'm not so sure Buddhism would have taken off during the civil rights movement. Not surprisingly it is Zen and the more intellectual branches of Buddhism to which Jews are drawn. Then there's the psychological thing. It helps you unlock mental traps you're in. I think that's a big part of the attraction and why Jews get involved with Buddhism.