The point I wanted to make is that using the term PED is itself presumptuous, and is not a wholly accurate description of the substances WADA decides to ban.
But fair enough. I'm not going to tell you your beliefs are definitively right or wrong, so long as we can agree what are beliefs and what are not. I think you are right to stress the health concerns from harmful side-effects -- all the more reason to be certain that the desired effect is "proven". Imagine a feedback loop when performance doesn't improve so athletes/coaches/managers/husbands decide to increase the dose.
Of course some of the banned substances can be performance enhancing, especially for women in the 800m, and there is some scattered evidence suggesting a potential effect for some of the WADA banned substances. WADA is very non-commital, suggesting they evaluate three criteria to ban substances, with no obligation to announce or defend or prove which criteria were met, if any. We shouldn't take it for granted that we understand the unpublished justifications of decisions made behind closed doors.
The supplement industry is a good analogy at helping us understand how willing athletes and non-athletes are to look for and use unproven solutions in a pill, and how lucrative that can be to exploit. Note that the supplement industry is largely unregulated by the FDA. From the FDA website:
"Before you decide to take a supplement, you should know that the FDA does not approve dietary supplements for safety and effectiveness or their labeling before they are sold to the public. Dietary supplement companies are responsible for ensuring that their products are safe and accurately labeled."
This makes it easy to understand why athletes would use them, especially athletes from cultures that looks for solutions in a pill, especially when soundly endorsed by unscientific rumors. In the case of DDR, (and in Russia/Soviet Union), it was not the athletes deciding to take the health risks, nor always aware of the risks. Didn't you just say something similar about Kenyans -- it is the coaches and agents deciding the risk and athletes having a trusting nature?