We have a word for it when people harboring some dark tendencies reach out into cyberspace and evolve their positions. It's called "radicalization". And why are they radicalized? Because every jackass can be heard. And those shrieking the loudest aren't our best.
The irony is that the very thing we celebrated the Internet for in the early days, it's ability to bring together niche interests and organize marginalized voices, is also its greatest weakness and probably its downfall. So assume you're in favor of LGBTQ+ rights. Yes, the Internet was a blessing to the movement, helping the community organize and build a voice. People who may be closeted were now able to explore their identities and ideas with others online even if they lived in communities that may have marginalized or silenced them. They could mobilize and take action on a scale unimaginable decades ago.
Now replace LGBTQ+ rights with something else, like racial supremacists or violent extremists from across the political and religious spectrum. The Internet has been a blessing to them, helping their communities organize and build a voice. People who may have secretly harbored those views were now able to explore these ideas with others online even if their communities frowned upon their beliefs and tried to silence them. They can now mobilize and take action on a scale unimaginable decades ago.
Of course advertisers want to fund the ragebait.
I'd put a nuance on it - it's not that advertisers prefer ragebait especially since it can come back and bite your brands in the ass when an angry host inevitably goes off the rails. Advertisers however seek the widest, most consistent audience, and this kind of angry content as you described is unfortunately what draws the most people. Nor do I think advertisers are the primary people to blame. The bigger blame falls on producers who'd rather chase the low cost, high listener content that maximizes profits without a care for social value rather than take a risk on new content. Its not that different from television producers who chase cheap reality TV or Hollywood spawning a thousand sequels rather than gamble on original storytelling. Low risk, high profit for mentally addictive thought "drugs".
Chemist who falls in acid is absorbed in work.