From my reading of the paper
the story isn't that WhatsApp is doing a nefarious data slurp, but that it's possible to decrypt its network traffic and extract forensically relevant metadata from it.
(http://www.fit.vutbr.cz/research/pubs/index.php?file=%2Fpub%2F10979%2FWhatsApp.pdf&id=10979)
Biting the hand that feeds IT
