This isn't a question of academic freedom or bias. It's a question of how to manage a classroom. Under ordinary circumstances, a professor shouldn't let a class "mob" a student for his or her ideas; the professor should keep the peace, settle people down, and let the student be heard. Now, if the idea in question is pretty outrageous, then you have a situation: you should let people criticize the idea, but not to the extent that they get personal and attack the student. (This is also a fundamental principle of Robert's Rules: criticize a proposal all you like, but do not attack people or attribute motives to them.)
Students shouldn't gang up on one of their own, and professors shouldn't let them. But people who make outrageous remarks should be prepared to deal with legitimate criticism.
The content of this website is for informational purposes only and should not be understood as legal advice. For help with any legal problems or concerns, including those similar to the situations described herein, a licensed attorney should be contacted. The contributors to this site do not claim or guarantee that the information provided is or will be accurate, correct, or effective in any particular situation, and should not serve as a substitute for competent legal counsel.