An RSS feed is an automatic notification that a writer has produced content and the content belongs to the writer and not to the blog site that is in receipt. Articles you draft and write on your blogger site is considered content that originated from you.
The RSS feed can provide content such as a link provide additional information once clicked, but it is not your original writing and is therefore not your content and can not to acknowledged as such. Content is the written work of the author and any other links got to be acknowledged and given credit where the credit is due.
An easier way of explaining content is that the RSS Feed provides internet information that origination belongs to the writer or whoever sent the RSS Feed. Just as the Hubpage tool provides capsules to further populate the Hubpage articles, it is not considered content. The written work contained in the Hubpage article is the content and not the capsules.