I'm glad that the initial ruling was overturned. Seeking out an advantage over others is competition. Other racers obviously feel threatened that an individual with a physical disability might have an unfair advantage due to his prosthetic legs. This despite the fact that as a species, we create our own obsticles called rules, and then we call it a game.
This is a (perhaps not uniquely; I'm unsure about that) human trait that we begin with in childhood. Who didn't at one point or another play "hide and go seek?" Who didn't play the expanded the rules, called "kick the can" http://en.wikipedia.org/wiki/Kick_the_can to include the idea of a safe zone? As the seeker, why did you count to 100? Why wouldn't you cheat? As a prisoner, why didn't you "escape" from your cell?
We do the same thing in our "professional" sports. There are a set of seemingly clearly defined rules that govern how we play baseball. When you are at bat, the pitcher delivers the ball over the plate, and then you swing your bat, making contact with the ball, only once, before trying to advance to the next base. When you run, your feet slip -- to overcome that problem, you wear cleets. Perhaps you can't hit as far -- to overcome that problem, you cork your bat. Hold on, they are both enhancements, which anyone can aquire, yet corking your bat is "illegal" against the arbitrary rules.
Boxing introduces this intersting notion of a cutman. During a boxing bout, it is the cutman's responsibility to prepare their boxer between rounds by controlling bleeding, and otherwise treating cuts and swelling. Without such treatment, you can be sure that the boxer would continue to bleed, or they'd continue to swell, until they could treat their injuries. Straight from Wikipedia on the subject, "A cotton swab soaked in epinephrine is applied with pressure to decrease blood flow even more." Adrenaline. Last time I checked, adrenaline is also "performance enhancing". Its treatment in boxing is somewhat more topical, but it is nonetheless allowed since a fighter who can see and who isn't bleeding, can prolong the match.
The point is that all our sports have aspects in one way or another that are either allowed by the rules or considered against the rules. Running, to my knowledge, does not explicitly make allowances for amputees to compete, but neither does it disallow. Like corking a bat before it was banned, we mustn't ban a runner because his limbs are slightly different. While getting prosthetic limbs will never be as widely sought as cleets, the rules must be reassessed. Each opponent seeks to "enhance" their ability; they either workout more, they get different equipment, they take steroids, they wear braces, they wear grease under their eyes, etc. This "infraction" is causing such an uproar because others certainly won't be able to use a similar enhancement... at least not in time for the Summer Games.