You need the DRM to go after one Kim Dotcom, instead of getting civil judgments from a thousand unremarkable people who were just doing the same thing that hundreds of thousands of other people do routinely and innocuously, without ever getting caught. You need it to narrow down the size of a class of people until it is safe to demonize and turn into examples, without alienating your potential customers.

Without DRM, when grandma gets sued for $10000 because she sent a copyrighted video to all 8 of her grandkids, the rights-owner looks like a bad guy. But when a nerd cracks the DRM and seeds a torrent resulting in thousands of downloads, prosecutors can pile on the computer crime charges, and it looks like the hacker is a dangerous criminal, who was probably stealing your identity and browsing through your cloud photos, too.

It's all about public perceptions. Shooting people in the head is somehow less acceptable if you didn't draw a line in the sand first. People get distracted from the main issue--which is people getting shot in the head--if the victims could have made some choice that would have yielded a different result. The public then gets fixated on where the line should be drawn, rather than taking away the shotgun from the homicidal maniac.