Take a look at these drivers who have been at the top of their respective motorsport. Shumacher, Dale E., Tony Stewart, Kurt Busch, Paul Tracy, Alex Zanardi, Juan Montoya. What do they all have in common? They are all agressive as hell and have punted their fair share of competitors during a race. It is up to sanctioning body to determine what is considered applicable racing technique. The snowcross officials obviously do not have a problem with bumping in the corners otherwise Blair would have been seeing a lot of black flags. I have raced go carts too and in my experience the real fast guys who usually won had no problem giving you the punt if they needed to get by. Us Gentlemen racers had a blast racing each other clean, and usually finished mid pack. However, we weren't being paid big bucks by a manufacturer who was expecting wins to sell their product. I don't buy into the theory that Blair gets special treatment. All three participating manufacturer's spend WAY too much money in snowcross to sit back and let the WSA give Blair a free ride.
The guy is fast, has stayed ahead of the competition for many years, and I respect him for that. I also was very impressed on how he bounced back from his moto - x accident in 2003 (compound fracture of the leg and cracked vertebrae) and still came out and won in snow-x 6 months later!! He is a great racer and the record books that have his name plastered all over them don't lie.
I am quite amazed at how many hate the guy, but I am biased because he is from my neck of the woods. Thinking about it, I have a hard time not hating Micheal Schumacher, who has dominated F1 in similar fashion to Blairs run in snowcross. I guess it's natural to hate the guy who has been at the top for a long time.