Linux World has a great post on "framing" and offers a good alternative example of why stopping DRM is important.
Here's the problem for the future, though. Documentarians typically don't reverse engineer media technologies. And the DMCA doesn't allow a developer to invent a DRM-circumventing tool and distribute it for non-infringing uses. So, without serious DMCA reform, the Digital Television Transition means we're likely to end up with a form of political speech, delivered via CableCARD, that's not legally available for the kind of quotation in context of criticism that previous media generations have grown up expecting.
If you're criticising Rupert Murdoch's politics, you don't have an alternate supplier of bits. You can't comment on his decisions regarding coverage of the war in Iraq and then paste in a Jonathan Coulton video to back it up. Some of the most important uses of information depend on copying bits from people who do not choose to enter into a commercial relationship with you.
This is a great argument to counter DRM advocates with.