It imagines a world where
#E2EE is made illegal or at least a cause for suspicion. It turns the tables by saying, this thing that I am saying... not only am I not ashamed of saying it, but I am using my identity to validate that it is me saying it.
A MAC-based identity/signing system is at the lower end of possibilities. If knowing that the signature matches a known identity gives assurances that this known identity is the source of the message, then why stop with a MAC? If I were to sign each packet with a string of the form "this packet is certified to come from the pen of and comes as part of a longer AONT message which is signed using the publicly-available PGP signature whose checksum is "
#Muddle is also a political statement. It's a not-encryption scheme that's just too stupid to beat.