Remember when Lance Armstrong got in big trouble for taking performance-enhancing drugs for the Tour de France, and he was lambasted in the media?
That might have been right and proper. But years later, I read that of the top 30 finalists that year, every single one was taking performance-enhancing drugs. Presumably the same was true in previous years. Armstrong just happened to be the first-place finalist in a year where they finally had the ability to start testing.
In a case like that, it's not enough to say "if you can't bike fast without steroids, then biking isn't for you!" If cheating is pervasive, those who can't or don't cheat will fall behind and quit, and all that's left will be those willing to cheat. From the POV of Science writ large, if the culture is rotten then the incentives must be changed. You can't rely on the independent integrity of every individual not to cheat, or you'll just end up with only cheaters.