You mention gmail which is a "mail" service, and whatsapp, which is a "messaging" service.

In all of (Western) history, those services have been considered one of the most private, like it or not. So changing that status (in the West) should require very public and very clear discussion, not just hand-waving about "child molesters".

Facebook: that is something totally different.

The fact that mail is handled by a private entity does not make it less mail than the official post. At all, and this has been understood (in the West) since, probably, the Roman times.