Why, exactly? Was anyone at risk of physical harm? It was clearly intended to be humorous, not as a call to action.
Where exactly do you draw the line between a joke and "hate speech"? Many contemporary comedians make rape jokes. Rape is a serious crime and it's an entirely reasonable conclusion to reach that such jokes would be grossly offensive and upsetting to a rape victim. Maybe comedians who make rape jokes should receive a knock at the door from the police?
Seems that the response of most people is "Ach, the boy's clearly a bit of a tool so whatever". If it was one of your favourite comedians being charged for saying something deemed offensive I doubt you would be so indifferent.
To be clear, I'm not saying that there isn't a line that shouldn't be crossed. But that's a distinction for us to make culturally and socially not a distinction for the law to make.