I'm not sure I understand what the moral dilemma is. It seems like the employees had to know what they were getting into when they took the job. At Facebook the users are the product. Everything is about capturing as much information about the users as possible so that FB can sell that information to their customers, the advertisers. Instagram, Whatsapp, Google are all the same, in fact pretty much every free service that people use on the internet.
There is nothing really morally wrong about what they are doing.