If the answer is predetermined and known it isn't a question. It is some sort of formal whipping and there is no point giving any answer.

From the peanut gallery it is plausible that Facebook is a net win or a net loss for adolescents and it is possible that the company has a staff psychologist who has actually thought about its impacts. That question is so hard to answer in the negative I seem to have 2 people answering in this comment chain as though the frame is obviously correct and Zuckerberg needs to answer yes then atone for his sins. Public hearings are not the place to engage with these sorts of questions (there might be consequences if he makes a mistake in his answers).