I assume he was using PEDs because everyone was and he was an exceptional performer among those people.
The notion that he was an exceptional performer who also had no issue breaking this set of rules but never broke that set of rules (which you have asserted he did not, even though it seems likely more players were breaking PED rules than impermissible benefits rules in general) is one I have trouble accepting.
But maybe I'm missing something — why do you think he wasn't?