I wasn't trying to explain how Eliezer's world works - I upvoted the original comment specifically because I don't know how it works, and I'm curious. If you were taking my explanation as an attempt to provide that information, I'm sure it came across as a poor attempt, because I was in fact specifically avoiding speculating about the world Eliezer created. What I was attempting to do was show - from an outsider's perspective, since that's the one I have, and it's obviously more useful than an insider's perspective in this case - the aspects how humans determine selfhood and boundaries that make such a change possible (yes, just 'possible'), and also that Eliezer had shown understanding of the existence of those aspects.
If I had been trying to add more information to the story - writing fanfiction, or speculating on facts about the world itself - applying your backpedal-ratio heuristic would make some sense (though I'd still object to your use of length-in-words as a measurement, and there are details of using new-concepts as a measurement that I'm not sure you've noticed), but I wasn't. I was observing facts about the real world, specifically about humans and how dramatically different socialization can affect us.
As to why the character didn't understand why people from our time react so strongly to rape, the obvious (to me) answer is a simple lack of explanation by us. There's a very strong assumption in this society that everyone shares the aspects of selfhood that make rape bad (to the point where I often have to hide the fact that I don't share them, or suffer social repercussions), and very little motivation to even to consider why it's considered bad, much less leave a record of such thoughts. Even living in this society, with every advantage but having the relevant trait in understanding why people react that way, I haven't found an explanation that really makes sense of the issue, only one that does a coherent job of organizing the reactions that I've observed on my own.
So does your lack of a sexual self make it so you can't see rape as bad at all, or "only" as bad as beating someone up? Presumably someone without a sexual self could still see assault as bad, and rape includes assault and violence.
As promised, here is the "Q" part of the Less Wrong Video Q&A with Eliezer Yudkowsky.
The Rules
1) One question per comment (to allow voting to carry more information about people's preferences).
2) Try to be as clear and concise as possible. If your question can't be condensed to a few paragraphs, you should probably ask in a separate post. Make sure you have an actual question somewhere in there (you can bold it to make it easier to scan).
3) Eliezer hasn't been subpoenaed. He will simply ignore the questions he doesn't want to answer, even if they somehow received 3^^^3 votes.
4) If you reference certain things that are online in your question, provide a link.
5) This thread will be open to questions and votes for at least 7 days. After that, it is up to Eliezer to decide when the best time to film his answers will be. [Update: Today, November 18, marks the 7th day since this thread was posted. If you haven't already done so, now would be a good time to review the questions and vote for your favorites.]
Suggestions
Don't limit yourself to things that have been mentioned on OB/LW. I expect that this will be the majority of questions, but you shouldn't feel limited to these topics. I've always found that a wide variety of topics makes a Q&A more interesting. If you're uncertain, ask anyway and let the voting sort out the wheat from the chaff.
It's okay to attempt humor (but good luck, it's a tough crowd).
If a discussion breaks out about a question (f.ex. to ask for clarifications) and the original poster decides to modify the question, the top level comment should be updated with the modified question (make it easy to find your question, don't have the latest version buried in a long thread).
Update: Eliezer's video answers to 30 questions from this thread can be found here.