Following the acquisition of the WhatsApp messenger, Facebook made changes to the privacy policy, allowing the company access to all user data.
source: https://www.theguardian.com/technology/2016/aug/25/whatsapp-backlash-facebook-data-privacy-users
archived source: https://wellthissucks.xyz/2016/08/25/facebook-collects-data-from-whatsapp-users-archived-source/