They started an exclusive podcast (Apple News podcast) and had some weird workarounds to hide the rss feed url from the iTunes directory API. It's still based on RSS and the feed url got leaked, so you can subscribe it in any app which uses the directory (and has added the leaked url to their own database), but people are fearing that they might screw around in the ecosystem

Joe Rogan's interviews with Tim Pool have covered corporate censorship in detail. Adam Curry and his co-host John C. Dvorak have also covered in detail on their podcast, the No Agenda Show, how a lot of this "censorship" on the part of corporations is a reaction to advertisers to demand brand-safety for their advertisements (eg: I don't want my ads showing up next to alt-right, pro-Trump content!) which is why Reddit banned The Donald and YouTube de-monitises videos that get even a little preachy or political. It's a real pickle for the companies because they are caught between bowing to their advertisers (which shareholder interest demands) and being free to the spirit of free speech in which they all believe.

Separating the definitive index of podcasts from a corporate entity allows corporations to save face with their shareholders without removing discoverability for content creators who are considered not to be brand-safe.