Each director gets a vote on a company board. Being a majority shareholder gets you to control who sits on the board, but you don't control board votes directly

Each director gets a vote on a company board. Being a majority shareholder gets you to control who sits on the board, but you don't control board votes directly. A company officer still has a duty towards the company as a whole and all the shareholders, even if they also control the majority of votes. Facebook is a public company, which creates additional safeguards to protect the interests of all shareholders.