Except that none of it is. She was tested extensively during 1988 even though it was not mandatory. She retired to have a child. IIRC some teammate sold a splash to the press about her and also Carl Lewis taking hormones but also had no evidence and struck out.
Need a far higher standard of evidence than "suspicion". As you do for biological gender which is why rules are not enforced against Caster Semenya just because "she looks like a bloke" or "she's too quick"
"After her death in 1998, Prince Alexandre de Merode, the Chairman of the International Olympic Committee's medical commission, claimed that Joyner was singled out for extra, rigorous drug testing during the 1988 Olympic Games because of rumors of steroid use.
...
De Merode was not without controversy himself, having been accused of covering up drug tests at the 1984 Games, and following record shattering performances by Chinese swimmers in the 1990s"
My bolding. Mandatory random testing was introduced in 1989. All FloJo had to do was dope up in late 87 and early 88, but tail off before major competitions. However, see the Carl Lewis article below.
Of Carl Lewis:
"Carl Lewis has broken his silence on allegations that he was the beneficiary of a drugs cover-up, admitting he had tested positive for banned substances but claiming he was just one of "hundreds" of American athletes who were allowed to escape bans.
"There were hundreds of people getting off," he said. "Everyone was treated the same."
Lewis has now acknowledged that he failed three tests during the 1988 US Olympic trials, which under international rules at the time should have prevented him from competing in the Seoul games two months later."
Drug abuse was rampant then, and systematically covered-up in the US.