historically, as far as the new left was concerned, it's genesis was just in anti-israel/anti-colonialist sentiment... there was always a part of the new left concerned with the Palestinian cause....

Rage Against the Machine had lyrics directly addressing this, I think it was in People of the Sun "Living in LA LA, like Gaza, on to the Dawn; intifada" - something like that....

the "anti-semitism" is just how its currently, derogatorily, framed, as it has become mainlined among portions of the left now...