Seems to me that there are two separate, though related, issues here. One is about the privacy of individuals. FaceBook, of course, hates privacy: it wants access to all of everybody, because every private area of our being is a potential loss in advertising revenue. But that’s specific to what Facebook’s business is.
The second issue is a more generic one. It’s a characteristic of computer “science”, and beyond that of other “sciences” in the modern world, to attempt to solve difficult problems by converting them into soluble caricatures of the problem and then declaring victory. Much of AI is like this, for instance, and the patron deity of subterfuges of this kind is the Turing test.
In FaceBook’s case, the subterfuge consists in pretending that communication is the expression of the individual, independent of its audience. This misrepresentation isn’t unique to FaceBook, of course: very few applications on the internet could function without it. But, as you rightly say, actual communication is something that happens in the recipient, not in the originator. You don’t curse in front of your (or, indeed, my) gran because you know that cursing will stop your communication getting through to her, which means stopping it being a communication at all.
How you know that, and what it means that you know that, seem to me to be part of a difficult problem — which is, doubtless, one of the reasons why FaceBook wants to avoid it. But another reason is that their model of communication can’t accommodate it: it has to be a model in which people shout into the void. The fact that they’re only interested in harvesting people’s desires is important in this (they really don’t care how people’s friends receive those communications, except insofar as they generate further desires,) but it’s also somehow incidental to a more fundamental maiming of the real nature of communication.
What do I know of you? Almost nothing, except that you say the sorts of things I also say. That’s good; but I have almost no sense of how I might communicate with you in the sense I’ve pointed to above, and to which I think you also subscribe, because that means knowing us ; and in a way that these forms, sadly, know nothing of. Sorry to run on, but once I get started…