I may be totally naive here, but I'm not really sure why this matters. That there is a WC3 standard does not imply that browsers have to adhere to it. If they didn't they simply wouldn't be able to access DRM protected content. From a UX perspective this seems no different from Netflix putting their content behind a login. Maybe I am being an idiot, if so please correct me, but this doesn't really seem like anything to worry about. The threats implied by EFF, that massive corporations will control content on the internet, seems only true for content published by those massive corporations (and thus are already happening now, with 3rd party DRM ie: Netflix's Silverlight player). It doesn't stop people from publishing non DRM protected content.
I would agree this doesn't belong in the spec on technical level, but it seems to be inclusive not exclusive.