Cheating is breaking the rules. If the rules allow all athletes to use doping then it isn't cheating.
I think what you are tyring to say is that using "artifical" means to enhance performance is inherently wrong, and I am challenging that belief.
Why should artificial protien supplements desinged to improve muscle growth be okay while a drug that improves muscle growth is not?
The body is simply a sustained chemical reaction. Why should someone whose body is chemically superior through genetics be allowed to dominate a sport as opposed to someone who can improve their chemistry by outside means? We already allow tinkering with the body's chemistry in the form of permitted "supplements" and drugs.
Science will only continue to blur the line between "artificial" and "natural" performance enhancements. It will only become more difficult to rationally explain why some ehancements are allowed while others are not.
How can some enhancement means be "wrong" while others are "right." People often cite "roid rage" as evidence that steroids are inherently evil, but many people take steroids without harmful effect. And what about drugs that don't have any outwardly harmful side effects? If the criteria for "bad drugs" is they cause violent behavior, then any drugs that don't cause violent behavior should be okay, right?
You could argue that some drugs destroy an athlete's body. But some drugs don't. And isn't it the athletes choice as to how far and hard he or she wants to push their body? Many athletes over train and cause permanent damage to their bodies? Should they be banned? How is that different that taking a drug that may have a harmful side effect?
And what about medications that affect performance? Why should an asthmatic athlete be allowed to take medicine that improves his breathing, and thus his performance, when an athlete without asthma cannot take advantage of the same drug? And what happens when athletes start developing "asthma" at higher than normal rates and get doctors to prescribe them this drug? How do you prevent an athlete from falsely claiming they have asthma or some other medical condition that requires a performance enhancing drug to treat?
Further, there is plenty of evidence that policies agasint doping are not being effectively and/or uniformly enforced. The result seems to be that many athletes are doping and only a few are being caught. Thus, doping has a net advantage.
Finally, I suspect fans are not as appalled by doping as popular media suggests. There seems to be a lot more outrage as a result of an athlete engaging in dogfighting than abusing steroids.