The people probably had a moral conflict: the good Facebook money but lose "their souls", or go with their conscience, quit and lose that money and work friendships/network. So, so they can sleep at night they've convinced themselves the company they're a part of wasn't the responsible party. So "Hey, those users opted-in, it's their own fault!".

Funny how it means the company is now probably full of either "ignorance is bliss" or morally bankrupt people, because the people with good conscience have left. Not that society at large is much different... what uncomfortable truths are we ignoring?