[Crito]

Obviously everybody should be busted for riding dirt bikes in cities, particularly in gangs (riding in gangs inherently means that several other traffic laws are being broken as well, and when they scatter when police try to stop them you throw in all sorts of additional crimes...)

In unpopulated areas? I'm sure the local police have methlabs to worry about, but sure, arrest them too if they ride on the street or trespass.

I am not saying that a racial discrepancy in enforcement is acceptable. I am just saying that the police taking issue with somebody riding around the city on a dirt bike is not necessarily the police making a mountain out of a molehill. If they are arresting only black people that do this, then the problem is that they are not also arresting white people that do it.