The saying is dont look a gift horse in the mouth, but the way Zuckerberg is consistently lobbying and pushing for the implementation of programs under an altruistic banner that also happen to largely benefit himself is somewhat counter productive.

Their is a reason most super wealthy people who have made a big impact through philanthropy have tended to make it their focus after they have explicitly detached themselves from their money making enterprise, and/or focused on areas that do not overlap with their money making enterprises...