A toxic stew of grievance, violence and social media

It didn’t take long, did it? Brian Thompson, the CEO of UnitedHealthcare, was shot and killed. Before police had finished cordoning off the crime scene, social media was on fire, turning the alleged shooter into some kind of folk hero. 

To more than a few Americans, Luigi Mangione, the man arrested and charged with killing Thompson, wasn’t a cold-blooded killer but rather a righteous vigilante standing up to corporate greed. He’s even been dubbed the “hot assassin” because of a shirtless...