Americans should not extend the copyright protections of the DMCA. Leaving aside philosophy for a moment, just consider a couple of practical problems:
More philosophically, we should not be surprised to see the march of progress render some industries different or even non-existent. Automobiles have replaced horses and carriages, and that is perfectly normal. We should not legislate horse and carriages back into economic relevance, and nor should we clamp down on private computing just so that content providers can avoid change. Fighting progress is no reason to give up our freedom.
For more information, go visit the Electronic Frontier Foundation. Particularly interesting to me is their enumeration of fair use rights that are under threat by DMCA. We need less of this, not more.