The spirit of sport is about fair competition, excellence in performance, and determination. Performance-enhancing drugs and doping run counter to these values, and therefore, the essence of sport.
The essence of sport is to provide entertainment through fair competition. The competitors that excel in their field, either through talent, hard work, determination, or biology, are afforded the opportunity to prove themselves against their peers. Doping undermines this entire premise of sport. It provides some competitors with an unnatural advantage, destroying the notion of fair competition, and unfairly penalizing those that put in the hard work to excel in their discipline.
Fair competition is only a fringe component of modern sport. While fair competition governs the rules of the game, it has no bearing on who can participate or not. If it did, those with a genetic advantage over other competitors would also be prohibited, as would those from wealthy backgrounds that could access better training and resources. Performance-enhancing drugs afford some athletes an edge in the same way wealth and genetics do. If anything, they may help close the performance gap between competitors from more affluent backgrounds and poorer backgrounds. Therefore, while competitive sport allows participants from all resource backgrounds and genetic predisposition to compete, it should allow doping.
Fair competition is part of the essence of sport.
[P1] Fair competition is part of the spirit of professional sport. [P2] Doping removes the element of fair competition. [P3] Therefore, doping goes against the spirit of professional sport. [P4] Therefore, doping should not be permitted in professional sport.
Rejecting the premises
[Rejecting P1] Fair competition is not a critical component of professional sport.