I suppose it's because after a professional racing career lasting 20 years or so, demonstrating her consummate skill at track racing at the Nurburgring, Sabine Schmitz has been picked solely because she's a woman, and for no other legitimate reason. Meanwhile Rory Reid, an up-and-coming motor journalist in various online sites and presenter on Sky Television, has been chosen not for his potential talent but because, entirely relevantly, he is black.
No such talent questions encircle Matt "I can drive a car quite well but it's hardly been the defining point of my career" Leblanc (who is, coincidentally, neither black nor a woman, and is therefore obviously chosen because of his talent and motoring background).