I think that her induction in the HOFs and the fact that she still is held in high regard, for the most part, is a testimony to the "pass" wording. As compared to Regina...
As to the doping culture of the time, I think that there is a general consensus that the playing field was not level in the 70's with the Viren and Cierpinski and in the 80's with Russia and the rest of the Eastern Bloc countries.
The US was keenly aware of this disparity and even 15 year old world beaters were not immune from the pressures of getting a "fair chance" to win. I mean, yes Mary was exceedingly talented, probably more talented than her Russian competitors, but why take the chance that drugs trump talent? So your argument that her talent increases the probability that she was clean before her bust in the 90's is no better than mine. My point is that the bust, which I agree is relatively weak, is just another "datum point" that shifts the conjecture scale towards cheat.
So no I do not believe her teenage years were drug tainted but it is very difficult to imagine a scenario where drugs weren't part of the equation in the '80’s and later.
Of course I'm as guilty of conjecture as you seem to be in believing clean talent beats drug talent but somewhere along the line the athletes have to come clean.
I agree with you that in order to accomplish this cleansing of our history there must be some way to salvage accomplishments. To a certain extent, steroids were uncharted territory in the 80's and a lot of people looked at them as more medicinal than cheating. This could be the window for allowing athletes to come clean. Until that happens, unfortunately for us, everyone will need to carry that burden of proof.