SINCE THE 2010S, social media has been identified with protesters. In the early years, this was intuitive. Protest movements wanted attention, but mainstream media outlets were often slow or reluctant to give it to them, unless, of course, things got out of hand, at which point they would get plenty. Social media, by contrast, was an effective tool for activists to communicate with one another and directly with the public, providing counternarratives to the ones laid out in the Establishment press. An opportunistic embrace of progressive causes by social-media executives cemented the perception: Twitter was with the activists.
This created a powerful dynamic: Social-media platforms that were used to organize protests were then used to circulate encouraging imagery of those protests, helping movements like Black Lives Matter spread across the…