Editorial: Anger and distress at the treatment of the stabbed teenager is widely shared. But the online amplification of myths and grievances must be tackled

Protesters angry over the murder of Henry Nowak and the way he was treated by officers after being fatally stabbed clashed violently with British police.

The brutal murder of 18-year-old student Henry Nowak in southern England has ignited another volatile debate in the U.K. over race and what’s been described as “white grievance.”…