It just means that there's always that fine line between those substances and medications that are legal and those that aren't, noting both are designed to give an additional enhancement to natural performance.

Some people stray over that line due to poor choices or bad advice, others don't but gain unnatural advantages through things other than just hard work and training too.

There's way too much money in sport to suggest that people won't bend/exploit the rules to give them the maximum, albeit allowable, advantage, whether a doctor signing off a TUE or those drugs which might not be detected or aren't yet on the banned list.

Its not as clear cut as some cheat and some don't, just that some are better at avoiding falling foul of the rules, whether through morales or money is debatable.