Look what happens when E2E is insecure, they help the kids at an alarming rate.

Signal

Sigint.

I haven’t used Whatsapp Groups. This says the analysis is from looking at who is in a group, so just metadata, not contents of messages.

That sounds like a normal marketing technique, though I don’t know how hard or easy it is to get a list of users in a group.

And also a phone number is Whatsapp is easy to lookup in Facebook and tie to a real person.

It’s all plausible without breaking into Whatsapp. But that doesn’t disprove inside information.