Again, I will defy popular opinion and make my unfashionable point:
What do we lose, if porn is banned?
Speech is political or social commentary, which is what actually needs to be protected. If porn gets banned, we don't lose anything that will improve our society. If politicians attack political and social speech as porn, it must be defended there, as it has been in past court cases like the ones legalizing Ulysses and Naked Lunch. However, political speech is much more easily censored by having six media companies control the news who refuse to report on certain things.
I think "free speech" as we want to practice is now is an illusion. It has a very bad consequence, which is that the signal-to-noise ratio becomes almost all noise. Even more, it prevents us from having a community with standards. When porn is common, everyone gets desensitized to porn and lets it shape their worldview.
In the name of freedom of speech, expression, etc. we have permitted ourselves to become crass and to support outright destructive ideas, and in fact force them on others, just to prove we're "open-minded" and that we like government and big media are supporters of freedom, liberty, peace, sexual liberation, diversity, porn, etc.