Every time it’s mentioned it’s only about sending e-mail to different providers, but the analogy doesn’t cover for example browsing your e-mail inbox and seeing communication from multiple sources. Just covering how one individual can send messages to multiple individuals via a common protocol is only half the picture.
Honestly it’s more like the old mailing lists (Majordomo days), where individuals would subscribe to a list, but that list might also subscribe to other lists themselves, and then you throw a web interface in front of it.
Also, those statements appear to conflict. Why are they automatically excluding ‘sensitive professions’ yet stating ‘it depends on the seriousness of the crime’?