I think that DRM for music is only maligned because the major players weren't able to come up with a single unified scheme (either for encryption or for encoding). As a result, it becomes a distraction, because not every song plays on any player. There are many incompatible formats that play on a subset of available players.

In the case of DVDs, everyone standardized on one scheme, and any DVD plays in any (region appropriate) DVD player. The encryption itself isn't really a problem, and no one complains about it (except for people who want to pirate DVDs).