After reading the other comments, I now know this isn't the case.. but I like to think that it's because he has doctor-like precision in his control of the bike. He can bring the front tire within inches of another rider without touching them. He also holds a very high level of mental strength and concentration when waiting for the right moment to pass. He seemed to study and pick apart his foes one corner at a time. He would just outlast them, mentally. I almost feel like he is much like Muhammad Ali in this way - he played a mental game and part of his success was not only precision and speed, but knowing when to use them.
5. Rossi has an honorary Doctorate in Communications from the University of Urbino
and thus became the DOCTOR. OFFICIALLY