The way he's using "fair" is more like "If sports were fair, then the guy who works hardest would win." Equality of opportunity, not equality of outcome.
Sports are fair in the sense that everyone has the opportunity to do everything they can within the rules. The rules are numerous enough and vague enough (being that they are written by people in human languages) that there are a variety of interpretations and paths through which one can play. No one person can explore the entire depths of the rulebook.
But it is not fair in the sense that any one particular path through the rulebook will be as effective as any other path.
That seems very obviously not true, unless by "primadonna athletes" you mean "the vast majority of athletes". Athletes face opportunity costs just like the rest of us, and different athletes come to different priorities. They aren't robots.
For instance, stories about pro athletes coming to training camp out of shape are very common. An article I recently read about Andre Miller comes to mind. Andre Miller is a basketball player that most would say fits the archetype of "wily veteran" rather than "primadonna". How does he train? http://espn.go.com/blog/truehoop/post/_/id/15542/the-secrets...
"I have no regimen," Miller says. After the season ends, so does Miller's working out -- no weights, no cardio, no nothing. "I really don't pick up a basketball." Eating right also falls by the wayside. "(My diet) isn't healthy at all," Miller says. "Hamburgers, hot links on the Fourth of July, all that." To control his weight, however, Miller uses old-fashioned discipline. "I starve myself," he says. Seriously? "Yeah, I'm just starting to learn about calories and all that."
Yep, that's the guy who owns the active NBA record for consecutive games played. And he competes against players like Kobe Bryant and Steve Nash who are famous for their impeccable training regimens.
Another example... literally every female athlete who gets pregnant is hurting her chances for victory. Yet tons of them do it.
That isn't clear-cut. There are rumours that getting pregnat was used as a form of doping. See http://www.snopes.com/politics/sexuality/doping.asp, http://en.wikipedia.org/wiki/Abortion_doping
That is incorrect. If sports were fair, then everyone would win. Sports are specifically not meant to be fair, the entire point of the competition is to reveal which competitor is superior to the others.
The rules that we have against performance enhancing drugs are not about having an advantage over other competitors. We don't have similar rules governing how much weight training a particular athlete may do, or how clean their diet may be. They are about establishing rules by which universal play can be governed. The rules of the game define the game. If you play by a different set of rules, you are playing a different game. If the Tour de France did not have a rule against excessive[1] steroid use, then using steroids would not be cheating. But, the Tour de France with steroids is not the Tour de France, it's a different race entirely.
As a culture, we associate healthful living with physical fitness, and we associate sports accomplishment with physical fitness, therefore we make the huge leap of associating sports accomplishment with healthful living. Even sans-drugs, sports accomplishment doesn't necessarily equal healthful living, especially in the cases of ultra-marathons increasing risk of heart attack and the head trauma of American football increasing the chance of dementia. But we still make that association, so as a culture we tend to value sports that at least pay lip service to maintaining the image of athletes as healthy. Though, it's important to point at that we are inconsistent in that regard: certain performance enhancing drugs are allowed in horse racing, and why shouldn't pain killers be considered performance enhancing, if they allow the athlete to perform better than they would without them?
Our culture shapes the rules we choose for our games, the rules define the game. Cheating is not about "gaining an unfair advantage". It is an unfair advantage for the New York Yankees to have the very best sports doctors in the league, but it is within the rules of the game, therefor it is not cheating. Much of sports strategy is about finding ways to find unconventional play within the rules to give oneself an unfair advantage. Cheating is violating the social contract of the game: "we've come here today to engage in a competition and these are the rules by which we will evaluate the competition".
[1] steroid use rules are often defined in terms of testosterone levels, and the limits are frequently well, well above the levels expected for a healthy male. The rule is thus, "no high testosterone", not actually "no steroids", and it has become standard practice in many sports to try to cycle a steroid usage to peak testosterone levels just below the limit. This takes significant personal experimentation and blood testing to see exactly how the individual body reacts to the drugs and over what time frame. But don't expect the difficulty to mean that people aren't doing it: they are. When you see an athlete testing positive for steroids, it is not a question whether or not they were using steroids or that others were also using it, it's a matter of them not following their regimen properly.