Which is more important?
Fair could be equated to a set of rules that everyone is aware of that allows all parties to come into competion with a more or less equal chance. Monitoring Hematocrit leves without concern for methods would be one example. There are plenty of others. We end up with what is probably very close results and an increased emphasis on tactics, and, bio chem.
Attempting to make the sport purely Clean would without doubt give a huge (10-20%) advantage to those who were willing to cheat and who get away with it. It would probably lead to larger gaps and a higher probability of the occassional fenom coming along that no one can match and who would dominate to the discouragement of many.
So, which is more important to you? Racing you have the opportunity to believe is "clean" or racing that you believe started with a fair and level playing field where there may be less chance of "cheating"?