This doesn't prove WhatsApp is encrypted at all. It proves that a directory of public keys is being logged and audited. That's it.
The protocol existing or being referenced doesn't prove it's what the production client is doing. That requires verifying the client code and behaviour end-to-end, not just the key directory.
The protocol existing or being referenced doesn't prove it's what the production client is doing. That requires verifying the client code and behaviour end-to-end, not just the key directory.