I am assuming that there is a company ("organizers of the event," as referenced in the article) handling the promotion of this, and that the company will receive a portion of the proceeds as their fee. So this is not pure profit for Cam.
And, as has been mentioned, Cam's already paid enough; he's not in it for the money. This is just the way that these companies work. They're not going to put their time into marketing this for nothing in return.
If you must blame someone, blame it on the company that organizes the event, not the athlete who's showing up for (relative) pennies.