It was becoming a familiar sight on Capitol Hill. In October, Facebook CEO Mark Zuckerberg, donning a suit and tie, sat in the hot seat and answered questions from US lawmakers for hours.

This time, Zuckerberg was grilled by the US House Committee on Financial Services about Facebook's latest venture, a cryptocurrency called Libra. Lawmakers were already angry that the company allowed hate groups to organize, facilitated child exploitation, failed to prevent breaches and allowed misleading political ads. Now, they worried, Facebook could wreak havoc on finance and let Zuckerberg, who received a skeptical reception when he testified following the Cambridge Analytica data scandal, hear their disapproval.