This is like the oil companies that hid the internal climate change studies for as long as they could. Zuck knew what he was doing long before everyone else did. Acting like he was just dumb and uninformed is wrong. When they started he might not have realized how bad optimizing for engagement was but it doesn't take a genius to realize what was happening with the data they have. He's not some starry eyed kid who accidentally made a monster, he found out he could become one of the richest men in the world if he made his monster vicious enough. This is a guy that started buying the land for his survival bunker 10 years ago.