@SAUNDERS @mhjohnson @FortyTwo Mastodon returns attachment links as media links not enclosures. If you want an ActivityPub based podcast tool get an account on a Funkwhale server which likely uses the same style apis for it's RSS feeds.
To block RSS access, a mastodon account has to be marked followers only so like when you visit its account page you get no toots. In such cases, a follower calls for the feed using their Mastodon login credentials in their reader