would come down just as hard on an artist who uses a bit of chemical creativity
Its a poor comparison - the point of sport is a level playing field - all the players on the pitch, all the horses on the track, all the fishers around the pond are playing with the same handicap. Fairness is the point of sport - the rules are what make it a sport rather than just gooning about.
Theres nothing fair about making art, music, film or whatever - there aren't any art-association rules that dictate what size of brush is valid for a given painting, or how long you are allowed to think about something before you write a poem about it, or whether I'm good at acting being sad or secretly arranging the abduction and torture of my own children so I can cry real tears in my oscar winning performance . So theres no unfair advantage. You can't cheat, other than in instances of forgery, impersonation and deception. (That would be the equivalent of wiggo winning the TDF then me locking him in a cupboard, sticking some fake sideburns on and accepting the trophy. - actually if I shed a few pounds I could pull that off)