Are you arguing that copyright and patent terms are not just unfair or unreasonable but *unconscionable*? Are you saying I should not be permitted to sell you a CD on the condition that you do not copy it?
It is a fundamental Libertarian notion that the government should never prevent two consenting people from making a mutually-beneficial agreement without an extremely powerful justification for doing so. I don't see an extremely powerful justification for prohibiting agreements of this kind.
I agree that it's hard to justify that prohibition from a libertarian standpoint, but as a non-hardcore-libertarian I see no problem doing so. I don't mind saying that you can't sell yourself into slavery, for example. And although I've got no beef with NDAs that protect actual secrets, I wouldn't mind banning contracts that require one party to avoid sharing information that's already been made available to the public, which is what a contract that implemented copyright would be doing. To sign away the right to discuss your own culture is to give up your own humanity, and I'd be delighted to see my tax dollars going to fight those who would pressure their customers into doing such a thing.