The GPL restricts what can be done with a digital object. This makes the GPL DRM.
clever, but no. the GPL is a license, which you are free to break at any time, although you are potentially guilty of copyright infringement should you do so. DRM isn't a simple restriction; otherwise telling you "stop posting stupid comments on Slashdot" would be DRM. DRM is a restriction enforced by some kind of technological mechanism (encryption or other). breaking a DRM requires a deliberate technological step, and is a DMCA violation and potentially, but not necessarily, a copyright violation.