I'm no fan of abortion, but this guy is an art teacher, so why is he using his authority to proselytize on a topic that has nothing to do with his subject matter? If this guy were a liberal showing his art class films about global warming, we'd all be outraged. I think he was out of line.
He probably considers it an 'art film.' According to the article, there were images of other things besides abortion, e.g. the holocast.