All of this brings to mind a basic undergraduate misunderstanding that I try to correct every semester, so here goes:
Free speech does not mean that every opinion is equal, it means that every individual should be free to have his or her opinions subject to the same standards of logical analysis. That means opinions can be presented, and tested, and some opinions can in the end be dismissed as less logically and intellectually valid than others. Free individuals are free to be wrong, but are not exempted from being told they are wrong when they are.