It's kinda buried and I had a hard time finding the original source, but "bridgman" is an AMD employee with knowledge of the hardware designs:
"the vast majority of our [AMD's] sales still come from the OEM PC market, which brings a non-negotiable requirement for DRM that can not be tampered with or disabled by the owner, backed by assurances from the HW vendor. Signing the microcode and keeping it closed are two things that help to get us over the (loosely defined and constantly evolving) threshold for "good enough" DRM."
His definition of microcode is any firmware, including the "security processor" that I've been choking on above -- he doesn't mean just the CPU microcode. This is the new and improved AMD though -- if something makes them look bad, they redefine basic terminology so it looks less bad.
Oh and DRM? Too bad the Oz citizens didn't reign in their crypto snooping law -- guess which hardware will likely eventually be leveraged to keep that nasty unauthorized open source encryption away from the masses or upload keys via side channel? Perhaps the thing that the user can't change but the vendor can be forced to, the thing that has the sole purpose of limiting what the user can do?
Clear enough now?