Tour de France 2009

I'd have said that this is arguably not cheating. it's 'organic', doesn't involve dangerous synthetic substances, and relies on the riders own physiology. if they want to do this, what's really wrong with it?

The same reason as always; if you 'allow' it it will no longer be a choice; everyone will believe their rivals are doing it so they will have to do it in order to be able to compete. And some riders will do it more than others, or take greater risks with their haematocrit levels and then it becomes potentially lethal. The Puerto case showed how dangerous blood doping can be; bags of blood stored badly, or injected in to the wrong person because of lousy record keeping (which is what nearly killed Jesus Manzano when he was a Kelme rider and teammate of Valverde).