“The time for self-regulation is over. It’s time we legislate to hold you accountable,” said Rep. Frank Pallone, D-N.J., the committee’s chairman.That legislative momentum, plus the social environment of political polarization, hate speech and violence against minorities, was reflected in panel members’ impatience as they questioned the three executives. Several lawmakers demanded yes-or-no answers and repeatedly cut the executives off.“We always feel some sense of responsibility,” Pichai said. Zuckerberg used the word “nuanced” several times to insist that the issues can’t be boiled down. “Any system can make mistakes” in moderating harmful material, he said.