It's worth noting that another reason the "fair playing field" is nonsense is that, unless we have truly Orwellian control over all athlete's bodies, we will never have 100% enforcement.
In other words, the playing field will be uneven by definition. In a hypothetical anything-goes scenario, at least an even "chemical" field is open to everyone, rather than the current situation, where it depends on the individual's appetite for risk (dodging tests, etc.)
It's also tough to deny that legalization of some PEDs would reduce risks of tainted chemicals, needle sharing, and other health risks that mostly are created by criminilization or banned substance lists.
On the other hand, it would raise the athletic bar higher in such a way that competition may not be an option for those unwilling to take the physical risks, and further degrade the quality of "sports icons as role models", whatever there may be left.
Excellent points.