I hear this often, but honestly even with a low pay people don't leave their job unless they at their core disagree fundamentally with the ethics of the company, and I don't know many people at FB who disagree fundamentally with the company. Sure there are people who are not happy with some of the decisions the company take, and they argue openly or challenge management about that, but a company can't make everyone happy and I'm happy that they at least give us transparency and the opportunity to express ourselves and challenge them when we don't agree. In other companies you would probably get kicked out if you didn't show open support in whatever decision they take, and worse if you start talking politics.