They don’t “host” the metadata any more than Google “hosts” the web pages it caches. When you create a podcast, you host the RSS feed wherever you want (not on Apple’s servers) and you submit the url to the RSS feed to Apple. Apple crawls the RSS feed periodically.
Once you subscribe to a podcast - either by clicking on a link from the podcast directory or by entering the url yourself - not an iTunes hosted url - the podcast app goes to your server directly.
Correct, and people would equally upset if Google removed search query links to Infowars' website pages, regardless of whether they like or hate the actual content. That's what this debate and people's concern is about.
Once you subscribe to a podcast - either by clicking on a link from the podcast directory or by entering the url yourself - not an iTunes hosted url - the podcast app goes to your server directly.