Well, they can't.
How do you expect them to talk openly and make a living?
Being too open like that can harm their income, either with current sponsors or the ability to gain a high paying sponsorship.
Representing a company manufacturing supplements, pre-workouts, and protein powders maybe requires one not to talk about exactly what he is doing with hormones on podcasts, even if it is not extremely high dosages.
If he is out there openly talking about 1200 test/ 500 deca / 300 tren (all made up) and growth hormone and insulin, then what company is going to want to sign him to a contract to pose for pictures with their supplements?
It is one thing to talk about it privately. It is quite another to go on a podcast with your name and face attached to it.
If they expect to make a living, they cannot be talking about it openly. Bodybuilding is not like football or baseball where being a competing "pro" means any money at all. The money comes from marketing for companies that make money selling stuff that will not turn anybody into a bodybuilder.