British front-line workers who were applauded on doorsteps in the early weeks of the pandemic now confront a torrent of polarization and misinformation. Doctors, teachers and other exhausted workers say they are feeling incredibly demoralized after reading social media posts insisting Covid-19 is a hoax or overblown. And that has had serious, real-world consequences in recent weeks, with demonstrators picketing hospitals and hurling abuse at health care staff.