@falcennial I'm no WhatsApp fan but aren't those messages encrypted at rest?
@falcennial @annika
These don't necessarily have to be extracted from the server, they can be taken from the device itself, where they are stored in the unencrypted form.
I haven't used WhatsApp in ages — since the stopped supporting Windows Phone, which was long ago, but I think there even was an option to back messages up to the likes of Google Drive, where they can later be stolen.