No, the politically correct thing to do is stop giving white people a "warning" while arresting black people as often as possible. The part you're missing is this: it's not that the police encounter 11.5 times more black people who possess marijuana. The issue is that upon encountering one white person and one black person who both possess marijuana, the black person is 11.5 times more likely to be arrested.
White teenager caught vandalizing something gets brought home to mom and dad. Black teenager caught vandalizing something gets brought to jail.
Arrest more white people and I bet you see penalties for marijuana possession drop quickly.