He did not teach for 13 years. He was a Teaching Assistant, a position that students take, usually during their post-graduate studies, that basically amounts to Professor's Lackey. A TA is not a professor and has pretty much zero control over the content of the class. He was initially defended by the school administration, then they quickly distanced themselves. Also, the comparison is Galileo is absolutely laughable.
As for the "He converted to a Semitic religion and speaks Semitic languages.", you and everyone else knows well that "anti-semitic" means "anti-jew", and your bizarre nonsensical defenses do nothing to change that.
ETA: I should also note that the school only allowed him to continue teaching if he assured them that 9/11 conspiracy theories would not be part of the course, which he had initially intended. He agreed, and presented 9/11 CTs anyway.