But when it became obvious that “ads” was the wrong mental model, and that the products being created were ultimately about the general problem of persuading people by using data collected by spying on them, it should have been realized this was an incentive structure that any sane code of engineering ethics should abandon. Facebook ended up being the best and most successful example of an organization taking this system to its most logical endpoint, but someone always would have unless a code of ethics managed to materialize upon seeing the damage it was causing before it got too far.
I don’t judge people who work at Facebook generally, but do think every one of them at this point should resign on ethical grounds. The situation could be fixed if the company (even just internally) owned up to the malincentives they have fallen into and committed to exiting it and leading on forming a code of ethics on when these kinds of system ought not be built.