You can't call it "repurposing" when you're using it for its designed purpose! RSS readers from day one have only ever been one aspect of the larger ecosystem around the format.
I see where you are coming from. Our thinking was that RSS was not designed to create an embed from a url, but for feed syndication in a standard format. This is definitely "repurposing" a standard format into an oEmbed type response for embedding.
I wasn't around then, but I'll take your word for it. In any case, the main point remains valid. We may see the decline of RSS readers, but RSS is alive and well.
If you don't know enough about a subject, you shouldn't write about it. Or at least do some research.
P.s. looks like you could have put your point in a tweet :)