He offers no proof, just “trust me bro”. If they actually had found flaws, they would’ve reported them. WhatsApp uses the Signal protocol, which is built by actual cryptographers using proper formal proofs. In contrast, MTProto is not designed from a formal cryptographic approach and is described by cryptographers as “brittle”. https://martinralbrecht.wordpress.com/2025/03/16/analysis-of...
Telegram also has no public security or cryptographic assessments, while meanwhile WhatsApp has had numerous components analyzed by cryptographers for security.