When you sit on a horse you are riding it. When you are sitting on a carriage that a horse is pulling, you are driving the horse. It seems this language carried over to motorcycles and horseless carriages. Since a car is self motivated, rather than being pulled by an external source it would seem most appropriate to say you ride a motorcycle and a car. Either way, I have to agree that you don't drive a motorcycle. You ride (operator) or you ride pillion (passenger).