Speculating a bit:
One of the forces tending to emancipate American lefties from their anti-anti-Semitic trance was the black movement -- I would like to come up with a better phrase for this, but I don't know what it would be. "Civil rights movement" is weak, "black nationalism" is just one strand among many. But anybody who was around at the time knows what I'm referring to, no matter what you call it.
^^^^ CB: Oh how about "Black liberation movement" consciously supporting national liberation movements around the world, in this case the Palestinian national liberation movement, and the Palestinian Liberation Organization.
^^^^^
The clearest-headed folks in this movement had very little use for Zionism, and they taught us palefaces a lot.
With all respect to the German comrades, they didn't have the benefit of this particular education.