Why there are no "secondary" sports league that allow performance enhancement drugs?
I mean, you'll find people using PEDs in any sport, despite the risk of bans and everything. Steroid use is also rampant among bodybuilders.
There is an "obvious market", but why do such sport leagues or federations that openly allow those drugs exist?
I can imagine that such a thing existing would create an immediate and widespread health problem with lots of people, athletes or not, using those performance enhancers and accidentally fucking themselves. But what else could be a problem?
An organization can't outwardly support it because that would be a legal nightmare once participants get hurt or die as a direct result of it. They may also struggle to get events sanctioned by the jurisdictions that they're hosting the events in.
That said, there are plenty that turn a blind eye to it as best they can, as others have pointed out.