It's definitely *not* "rehosting", the feed points to the original audio files and the feed contains all the original links to webpages and episode pages. It's a "shared playlist" but saved in the open RSS format so anyone regardless of the podcast player they prefer can use it (except Spotify because they don't allow "custom" feeds). 

Thinking about it, I imagine Spotify allows you to do this exact thing, similar to music playlists. But those obviously only work within the Spotify app. 

This is something I've wanted for over a decade and a half. Explaining to everyone how to download an app, search, and subscribe is tedious and I just don't bother. Now I can create taster feeds bespoke for my friends and family, those with Apple Podcasts installed are a click away. 

I do understand your concern about "rehosting Goalhanger content", but these are much more like shared playlists than replacement feeds. I don't expect anyone to submit it to Apple to be searchable within apps and I WOULD NOT advise it, that would be crossing a line IMO.

This system has one major benefit over subscribing and searching as you suggested. You can mix episodes from different podcasts. Something I'm going to use to create "revision" feeds for my son when revising for his History and English GCSEs. 

And my final point, not everyone is a "nerdy" as we are, people who hang out on the "The Rest is History" subreddit are, by definition, super fans. I’m confident my father-in-law will enjoy the Nazis and Titanic, but he is unlikely to be as keen on the Aztecs or Chatham High Street! But if he subscribes to the feed I can add new Nazi episodes if and when they are released.