A lot of the service they provide is figuring out how to load out of spec or outright broken feeds. They had some blog posts on this back in the early post-Goog

A lot of the service they provide is figuring out how to load out of spec or outright broken feeds. They had some blog posts on this back in the early post-Google Reader days. A self-hosted option will eventually fail to load a feed, and there's not much you can do unless you're a developer.