The professor has a right to advocate a position in class as long as he does not stifle free conversation or grade in a prejudicial manner based on opposing ideas. Advocating his opinion can and should function as part of the free exchange of ideas.
Specific questions: Is the purpose of education really to make sure students have all possible information? You might think the purpose of education is to create people who are critical thinkers, or to create people who are easygoing and not too judgmental, so that they can get along easily, or to put children in an environment where they can learn how to socialize, or to indoctrinate people so that they believe the appropriate things. On another note, I think there might be a slippery slope worry here: should a professor teaching evolutionary theory be required to present creationism as a serious alternative? Should a professor teaching political theory be required to present fascism as a serious alternative? I worry your argument would require you to answer “yes” to both of the above questions, but I’m not sure.
Jen's Prof. lecturing on the benefits of animal testing Case Notes, 3/15/11
Position taken: The professor is permitted to advocate his view in class, but only if he fairly presents both sides of the issue.
--don’t want to restrict the flow of information, which is key to the learning process.
--need to present both sides because all information needed to formulate own opinion
--unreasonable and unfair to only present one side, because students not in position to judge it without all of the relevant information
--if restrict, students can’t learn about controversial ideas, which again, is key to the learning process
--purpose of education is to share information, so the refusal of the professor to share both sides is irrational, insofar as it is contrary to the purpose of education.
--also, because of free speech reasons, want to restrict the professor as little as possible
General notes: The focus on the purpose of education is good, because then you can clearly show what follows from that. It would be good to streamline this argument a bit; it seemed slightly repetitive in places. Also, I think it might be helpful to point out the related, but not clearly stated, argument that the professor is in a different position than just any person on the street. In virtue of being their professor, it seems like he has a special obligation to his students, namely, the obligation to present all sides of the issue as fairly as possible. I think this argument was implicit in your presentation; it might help to bring it out more fully.
