Earlier quoted context omitted.
i dont think users of whatsapp would have standing against people hacking whatsapp to get their data. whatsapp owns the systems, so its up to whatsapp to sue
What? So if someone robs a bank and empties my safety deposit box I can't sue them because it was the bank that had the money, not me?
You can sue the thief for stealing your property and the bank for negligent bailment. Same concept as a valet crashing your car.