A racist screaming the N-word and a Black person using it in conversation are poles apart. Why can’t the CPS see it?

‘A tweet by a 21-year-old Black woman was picked up by a data monitoring organisation – and months after it was posted, the police were at her door.’ Photograph: Westend61/Getty Images

It was summer 2014. Driving back to London with my baby daughter after a day out in Waltham Abbey, I was waiting for a traffic light to turn green. Pulled up beside me on my right-hand side was a long-haired, long-bearded man on a classic motorcycle. He looked around my car, and shook his head in seeming disapproval. Suddenly – with absolutely no provocation – he roared out “FUCKING NIGGERS”. Then he jumped the red light and sped off.

Every decent person could see that as a credible hate crime. But there are exchanges less clear cut, with motivations more arguable. How should society – and the law – deal with those?