Many Cooper Union lectures are open to all. It sounds like this one was, too. Here's a
blog entry from the type of lefty who attended. They were not all students. There were even some Hassidic Jews in the audience, for some reason. Chavez used them as a prop to claim that he had Jewish friends but was against Israeli aggression.
Moonbat Harry Belafonte introduced Chavez, for what it's worth.