How Do We Get to Herd Immunity for Fake News?

Last week, veto-proof majorities of the House and Senate rejected President Trump’s demand that they use a defense-spending bill to repeal liability protections for social media companies. The demand arose from Mr. Trump’s frustration with platforms like Twitter for taking more assertive measures against misinformation and disinformation, including his own.

Yet the chorus of angst over misinformation has focused too sharply on the channels supplying it. The bigger problem is the public’s appetite for consuming it.