The only upside to chasing the driver and having police capture him is had the car been stolen they would have been able to prosecute. Since that wasn't the case (determined only after-the-fact), once the license plate number was obtained, the chase probably should have ceased.
By continuing to pursue the Benz, the biker likely only increased the desperation of the hit & run driver... causing him to run additional red lights and put others in greater danger.
I'm all for making the guilty pay, but not if the ensuing chase results increased risk to the rest of the motoring public.