Amid the Capitol riot, Facebook faced its own insurrection

As supporters of Donald Trump stormed the U.S. Capitol on Jan. 6th, battling police and forcing lawmakers into hiding, an insurrection of a different kind was taking place inside the world’s largest social media company.

Thousands of miles away, in California, Facebook engineers were racing to tweak internal controls to slow the spread of misinformation and inciteful content. Emergency actions — some of which were rolled back after the 2020 election — included banning Trump, freezing comments in groups with a record for hate speech, filtering out the “Stop the...