Freedom of speech is a difficult subject because if you don't allow one retarded opinion, then the way to forbid another opinion is not far away.
I hate that fucked up pile of shit organization that is NAMBLA more than creationists hate the truth and I don't think anyone should specifically defend their rights to say that 8 year olds enjoy getting raped, and nothing would make me happier then to see all of their members locked up behind bars so they couldn't get near children at all.
Unfortunately though you can't imprison people because of their opinions no matter how much you dislike them, if we start doing that then the USA will become a "communist" country.
And we don't want that, do we?