I worked at FB (not for very long) but you can trace everything back to the awful performance process they have (the infamous PSC). At the end of the day, hard to measure stuff doesn't get you promoted while tangibly moving metrics does. If you incentivize people that way, it doesn't take anyone WILLINGLY doing anything evil to end up with a pretty evil thing on your hand.
If you optimize for profits and only that, you always end up selling crack cause it's the best business in the world, and that's why it's illegal.
I agree their incentive structure is at the root of this. But this is an incentive structure designed by one group of conscious actors and then followed by another group. A bunch of people choose this. And given the many years of public critique of Facebook, they can hardly be unaware of what they're choosing.
The truth is that almost anybody could sell crack. Most of us choose not to.
If you optimize for profits and only that, you always end up selling crack cause it's the best business in the world, and that's why it's illegal.