I don't think Haga ever thought he would win this season's championship, regardless of what he said. Last year, before Haga lost his points, and before Yamaha pulled out of WSBK, Haga stated in an interview that he did not like riding 2-stroke machines. I think it was a Bike, Performance Bikes, or another British rag that had the interview.
Because of what he said then, i think he intended this GP season to be a chance to learn the tracks. I believe the only reason he was brought to GP was to race the 4-strokes. So, basically, Yamaha just put him on a 2-stroke this season until 4-strokes are allowed to race.
But, in regards to what he said; what do you expect?? I doubt any factory would let their riders go around saying anything but that they expect to win everything.