https://qz.com/1117340/why-facebook-ceo-mark-zuckerberg-is-not-testifying-before-congress/

As Facebook begins its second day of testimony before Congress, we shouldn’t expect to see its most public faces, CEO Mark Zuckerberg and COO Sheryl Sandberg. Instead, lawmakers will be grilling tech company reps who are more used to confrontational questioning: their lawyers.

Although many have called for Zuckerberg to appear, there are several reasons why Facebook, as well as Twitter and Google, picked their counsel instead of their executives to face senators and representatives.