To the op your question would be best posed to the event organizer.
Take a look at the resume of a Nick apex and Ernie vigil compared to any stunter from our country, they are leaps and bounds bigger and better. However to have them come to our country for a stunt show is odd, considering no one outside of a very small stunt community knows who they are. Therefore the crowds mind can be blown by Joe Anyone Ontario.
I think Johnny hit the nail on the head. The U.S riders sponsors are stepping up in a big way to get them here and mostly foot the bill. Even if the organizer did contact local talent, it plays out like Johnny said. Nick and Ernie are sick riders, it'll be a good show regardless of politics : )