Rossi is not only the best bike racer in the world, he's also the noblest.
He knew how much anticipation there was for this race from the 2 American riders, he saw they had a decent drive in they're spirits and knows he already carries the 05' GP championship in his shirt pocket, so he said to himself (in Italian of course): "What the hell, I'll let them have they're 15 minutes, it's not like they'll win anything back in Europe and they won't change anything in the top of the chart, so my friend Marco will still be 2nd." And then he just continued cruising down hill in neutral while he enjoys the view.
I really didn't see any fighting spirit in the way he was riding in Laguna, definitely not the Rossi that kicked Sete out of the race in the last corner in Spain (and braking his spirit completely by doing so).