"But hello! American lefties don't even feel allegiance to AMERICA--their own country! Why would they be any better vis a vis Israel. It doesn't make sense to be baffled by this."
That was helpful...a little.....But you would think an image of box cars taking your ancestors to Auschwitz might inspire a New York Jew who witnessed 9-11 first hand to support the best friend Israel ever had.
You're missing the point. They aren't looking for Israel's best friend. They don't respect Israel any more than they respect America.