I think it's just the world. Joe Rogan is popular because currently "Joe Rogan Things" are growing (Weed, fitness, nutrition, MMA, psychadelics). These are all trending.
There's likely a feedback loop involved. Commentators who happen to talk about trending topics become popular; their popular platform can bring those topics to a broader audience; that broader audience stokes the hype around the trend and builds the audience further through (social media-amplified) word of mouth.
It's still rare for a celebrity to be as gung-ho and upfront about drug use, while also being very healthy. Usually drug use and celebrities are mentioned together in tabloids along with calls for them to go to rehab.
