To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;
Sorry, don't see how the DCMA works with that. Yet another undiscovered clause of the constitution that makes it a federal issue to protect rap songs for a period of the author's life plus seventy years - Just impossibly long to begin with, and it's hard to argue that music is 'useful arts'.
But it is a "writing" (or at least the publishing of it is) and is entitled to protection under copyright law. I do agree about the excessive length of most copyrights, especially Congress's penchant for retroactively extending copyright lengths.