The constitutional source of the copyright laws of the United States is very different in spirit than the copyright laws of much of the rest of the world. WIPO so far has had a very non-US approach, which tried to give absolute power to the copyright holders, and we adopted WIPO policies as our laws in direct opposition to the spirit of the Constitution. Not only the WIPO-based DMCA, but the CTEA and others influenced by the international community have made our copyright laws stray very far from their constitutional basis.
It is good that WIPO is moving towards a US-based model that balances copyright holders' limited monopoly powers with the public good.