It reflects the fact that DRM is a fundamentally incoherent concept -- you can't provide data and all the tools for legitimate users to access it freely and still deny illegitimate uses of the data.
1. Lack of common sense or just "following the herd" (Lysenkoism).
2. Covering one's incompetence. (Poor sales are blamed on piracy, and DRM is used as a demonstration that they are "doing something about it").
3. Controlling technology progress and direction (like standards poisoning and so on).
And etc.