The human vulnerability of WhatsApp group chats - an anecdote
WhatsApp claims it uses end-to-end encryption to secure the content of your chats. You might interpret this as implying that WhatsApp does not know who you contact through its app, but they do. Only the content is encrypted, not the fact that you contacted someone. Morever, the name of group chats are not end-to-end encrypted. Worse still, WhatsApp actively polices this information.
How do I know? I’ve experienced this first hand by being member of a group chat where one of the members decided to rename an existing (5+ years) group (15 members) to Condolences register for Ali Khamenei. The group was banned on the same day.
I am not here to defend or attack the taste in humor of others: de gustibus non est disputandum. What I am here to defend is the privacy of everyone, as the lowest common denominator applies. In this specific case, the actions of one group member resulted in the banning of a group and, in all likelihood, the inclusion of everyones phone number on some (hopefully only internal) grey list kept by WhatsApp. In the best case scenario, this information will only be shared with the relevant authorities upon their explicit request.
Any intentional holes in end-to-end encryption which are only there to facilitate monetization can and will be used for other purposes. Even if you believe you have no need for privacy for your own actions, guilt by association might only be around the corner. If you can, use Signal.
Update: Meta will remove end-to-end encryption for message content on Instagram.