Facebook is the biggest farm of data milch cows that has ever existed. How can he publically come out and say that? Yes there are, and will continue to be unintended effects on society for running such a large farm...

But

Everyone (trapped) employed in the credit fuelled consumption economy needs the farm to exist.

Asking Zuckerberg to clarify the role of the farm is pointless. It's like asking why a gigantic herd of wildebeest are required for the Serengeti to exist.

If you want a consumption culture that gives you, your iPhones and Star Wars movies you need the farm. Whether its called facebook or is run by a Zuckerberg is in an irrelevant point.