There are places on the planet where the natural urge for free expression is not allowed. The United States has never been one of those forbidding spots — until now. Like a smoldering match dropped too close to a gas pump, the inexcusable police killing of a black man has blown racial sensitivities sky high. The resulting concussion has stripped away the great American tradition of searching for a pathway to peace through reasoned discussion, replacing it with robotic recognition of systemic racism. So much for unfettered speech in the land of the free.