This has long been a bit of an elephant in the room when it comes to "giant publishers talking about piracy", so naturally it's taken a representative from a small publisher to bring it up.
Asked by GameSpy why companies like Ubisoft insist on hideous forms of DRM, Paradox Interactive CEO Fred Wester replies with a healthy dose of practicality:
I think there's a lot of politics, especially in bigger companies. It's simple for me being the CEO and half-owner of Paradox. I can basically call the shots I want to call, and if the board wants to ask questions it's like ‘OK, we can take this into consideration.' If you're a CEO, you need to cover your back. And the people who ask, the board, know nothing about games. They're there because they're some investment company or something, and they ask "So what are you doing to protect our game from pirates?" And then they can reply "We're buying this solution from Sony." So I think it's been a way to cover your back, previously. Now, I see no reasonable explanation for why people keep on adding it. Especially the kind where you have to be online all the time, like Ubisoft. I think that's, to me that's 2003.
If you've ever wondered why publishers persist with DRM when they must know it does little to stop piracy, that paragraph above makes more sense than almost anything else I've ever heard on the subject.