The killing of UnitedHealthcare CEO Brian Thompson on a Manhattan sidewalk, allegedly by Luigi Mangione, led some people to express anger at health insurers.

The killing of UnitedHealthcare CEO Brian Thompson on a Manhattan sidewalk, allegedly by Luigi Mangione, led some people to express anger at health insurers.

Shane Daley of Galway, N.Y., left mocking and threatening messages for a family member of Brian Thompson, who was fatally shot in Manhattan last year, according to charges filed…