I think that’s a different situation. That’s taking a story, or really the themes of a story, and rewriting the entire thing into a different setting. The story is fundamentally changed, and it’s very much NOT the universe created by Jane Austen. That’s a legitimate reimagining of a similar tale. It’s not like there are many stories out there which are totally dissimilar to all other stories in the world.
I’d not raise an objection to someone taking the themes of my story and writing their own, the themes are hardly original to me. And even if their version was set in a setting very similar to mine, that’s not so much a big deal. It’s when they take my exact characters, names and all, my worlds, names and all, my nations and wars, names and all – my precise elements which I have been building and revising for close to ten years – and just use them as is that I object. Those are mine. You want to tell your own story that has a similar feel to mine, that has a similar theme to mine, that has characters who draw from the same archetypes as mine, go for it. You can be the Go-Bots to my Transformers. But stay the hell away from that which I have specifically created and designed.
And frankly, when it comes to Internet Fan Fiction, I don’t so much care. I doubt anyone’s ever not bought a book because some lame slash or fan fiction on the Net. It’s still quite lame (though when I was 12 I did write part of a Star Wars fan fic, but I never finished it).