The Dangers of Microsoft Pluton

I'm completely missing how his example of a Word document that can only be opened by approved users on approved hardware within the corporation is supposed to be a bad thing.

Honestly, that sounds pretty fantastic. I've been using 3rd party tools/extensions to do this sort of thing in corporate and government environments for years, but having the attestation go all the way down to the hardware level is a big value-add, especially with so much ransomware/spyware/extortion/espionage going on these days.

Can someone please explain to me how the author might see this level of security as a bad thing?

Remember when Snowden and Manning leaked huge troves of secret information about the crimes of the State? Remember when a bunch of journos got their hands on the so-called "Panama papers"?

Basically, this will make transparency even harder than it already is. That's a terrible danger for democracy at large. Stalin's wet dream.