I don't get that. Say Disney has a Lion King DVD. Why should attempts to stop you pirating it with DRM tech mean they shouldn't have copyright protection?
Because copyright is temporary, it is a legal protection allows one to exploit a their work. But when the protection expires works should be accessible for the public good.
If the public cannot access a work after copyright expires (because of DRM) then then the company will never contribute to the community-good in return for the protection they receive.
Those US Founding Fathers were all about laws that ensured progress of Science and useful Arts[0]. Or some such.
