Former Facebook policy executive Sarah Wynn-Williams has been barred for more than a year from speaking about her scathing memoir detailing her time at the company, even as it hit No. 1 on the New York Times bestseller list. Now she is suing Meta Platforms in federal court, alleging that the arbitration enforcement action that the company brought to prevent her from promoting the book, and the underlying contract it is enforcing, are invalid. “Careless People: A Cautionary Tale of Power, Greed, and Lost Idealism” alleges a range of wrongdoing by executives at what was then called Facebook, including being willing to…