More on Backdooring (or Not) WhatsApp https://www.schneier.com/blog/archives/2019/08/more_on_backdoo.html
Bruce Schneier is a journalist. He's not a sysadmin.
There certainly is a legitimate story about Whatsapp backdooring out there, namely that this is a feature that the UKUSA Pact, the so-called "Five Eyes," want in order to enable their universal surveillance over this "secure" app.
"Calls for backdoor access to WhatsApp as Five Eyes nations meet
Countries focus on increasingly effective encryption of communications"