Copyright infringement is different from theft
Although the media industries like to confuse copyright infringement with theft*, it’s not the same thing. The Los Angeles Times has a nice article covering the subject: File ‘sharing’ or ‘stealing’?.
* For instance, the annoying would you steal… trailers, at the start of DVDs.
Whilst on the subject, the fact that you cant skip these messages about not viewing the DVD on an oil rig, etc. is a fine example of DRM – which should be enough reason for anyone to conclude that DRM is a Bad Thing.