The divide at the top of sport is huge. To really compete you need money. Money for equipment, training facilities, coaches, to live while training and devoting your life to your chosen field.
If you add drugs to this the gulf gets even wider. It becomes who can afford the best doping enhancement plan to win. The rich get richer,the poor get poorer.
To even argue that drugs should be allowed is without much thought to the consequences for sport and the health of those in the sport. Every sport has its cases of people losing their lives too young from drug use. If money is devoted to usage for those with money, well maybe those deaths will be lessened but you can be sure that cheaper drugs will become available to less wealthy nations or people, and the consequences will be the same if not worse.
As has been mentioned sport is man against man and man against himself. It is not about how fast a man goes up a mountain, but how he competes against the others that do the same.
People who want win at any cost lose perspective on what it is all about. Scientists use science and debate its merits. With epo and other performance enhancers great feats can be done. But do them in the name of science and endeavour so all know what can be done, not in the name of sport.