That's a good point Mefty, the difference between peformance enhancing and pain relieving drugs.
The whole debate is far more complex than the popular media ever engage with and for that reason I think popular opinion is deeply misinformed about the issue.
Yyour average guy in the street wouldn't have the faintest idea what EPO does or how someone comes to be banned for its alleged use. For example at one point (not sure about now) you would be banned from racing purely for having a haematocrit level above a regulated point, not for having tested positive for EPO (I don't know how realistic the claims of having naturally high haematocrit levels were).
Similarly, is the practice of having your own blood transfused into your body before a race cheating or not? If you have a blood transfusion for medical reasons, does that make it OK in that context but wrong if it is for other reasons? What is the ethical difference between taking nutritional supplements and 'blood doping'.
I agree there is a difference, but I don't think it's well debated or understood in the mass media.