Maybe they have mistaken assumptions about Zuckerberg’s charitable intentions
The Winklevosses — identical twins and Harvard graduates — say that they, along with another Harvard student, Divya Narendra, had the original idea for Facebook, and that Mark Zuckerberg stole it. They sued Facebook and Mr. Zuckerberg in 2004, and settled four years later for $20 million in cash and $45 million in Facebook shares.
They have been trying to undo that settlement since, saying they were misled on the value of the deal. But it has not been an easy decision.