Freedom is freedom for truth. Error has no rights. This was the perspective of the Church for many centuries. It was used to support censorship and persecution in many countries. The same perspective was employed by Protestant countries for the same purposes and by non-religious dictatorships. The freedom was the same; the truth was different.First of all, Church teaching cannot be contrary to human dignity, and if you think it does, then you don't get Catholic teaching. The doctrine that "error has no rights" has not been overturned and is still correct, even after Dignitatis Humanae. Persons, however, do have inalienable rights. But I would hold on to the principle that there is no unconditional "right" to spread error, especially harmful error. This does not grant a right to religious institutions to actively suppress error outside its borders. The Vagina Monologues is not a person; it's a play. A university can ban a play from campus. A university can limit what a speaker may or may not speak on if she's invited on the university's dime. To assume that the principle inexorably leads to bloody persecution and repression borders on paranoia. So let's get off the pre-Vatican II Church's back -- it's getting old.
At least with respect to the actions of government, Vatican II changed the perspective of the Church. Vatican II respects the dignity of the individual and his or her freedom to make religious choices. It respects the right of individuals to choose error, but hopes to lead them toward truth. As I understand it, liberal Catholics believe that individuals should enjoy the same freedom with respect to Church teaching. They should, for example, have been free publicly to maintain that religious freedom was demanded by appropriate conceptions of human dignity when Church teaching was to the contrary.
What is almost always overlooked is that the erroneous viewpoints being pushed onto Catholic campuses are not just at variance or at odds with Catholic teaching; they're utter nonsense that do not deserve the respect of university-level discourse. Just because a lot of university-educated people love it doesn't magically transubstantiate bad milk into good meat. VM is not about expanding the debate; it's about pure mockery of any other viewpoint but its own. If it affirms anyone, it does so by way of incitement to hate everything that differs from it. That kind of material belongs on Jerry Springer, not a university campus.