alt Hacker NewsAccidentally replying in plaintext is a user error, scanning a QR code is a user error.
Yet one system is declared secure (Signal), the other is declared insecure. Despite the fact that the QR code issue happened in a war zone, whereas I have not heard of a similar PGP fail in the real world.
First of all, accidentally replying in plaintext is hardly the only problem with PGP, just the most obvious one. Secondly, it's not user error: modern messaging cryptography is designed not to allow it to happen.