The mainstream media push against podcasting is really a fight to hold for their power.
People who think they have the power to tell people "what's going on" are annoyed that a mere "podcaster" can also do the same nowadays. It's pretty interesting when you start to notice the derogatory tone mainstream-media celebrities use when talking about podcasts. The idea that some rando (in their mind) can just skirt the whole path they suffered through to get where they are, and have enough power to have their say and affect people's mind. People in this group include people like Don Lemon, Chris Cuomo, Matt Lauer, Jake Tapper, etc...
Those television journalists have it in their mind that they're the authority, and their authority is being challenged now by the fact that a podcaster is becoming more and more of a big-shot.
It's pretty much the same push initially against youtube, social-media, and possibly even the internet, before corporate media managed to find a way to use those tools to their benefit. This also explains the push for monitoring, regulating (aka controlling) what's being said via this medium.
Mainstream media is not just TV "journalism", but also the rapidly deteriorating online/print journalism:
- https://www.brookings.edu/techstream/the-challenge-of-detect...
- https://theguardian.com/media/2020/dec/12/sinister-sounds-po...
- https://www.theverge.com/2021/12/7/22821823/joe-rogan-media-...