“Facebook Messenger offers end-to-end encryption, meaning chats between two users will be visible only on users’ phones and aren’t readable by Facebook or any government entity that makes a legal request to the company. But the option is available only to people using the Messenger app on mobile devices, and messages are encrypted only after users select the option to mark chats as “secret.””

From their linked article.

It’s insane to only have E2EE as an opt in feature.

This is about whatsapp.