rainisto: DRM means any kind of taking away control from the user by means of obscurity, closed encryption and so on. Locked / encrypted bootloader with no way to set your own keys or unlock it is a perfect example of DRM. That's the way I understand the term. Preventing copying media files is just one example of it.

Protecting data and security with encryption is perfectly fine, as far as the user is in control of that protection. If user isn't - that's already DRM.