Why would it be right to help people to have more fun if helping people to have more fun does not match up with your current preferences
Because right is a rigid designator. It refers to a specific set of terminal values. If your terminal values don't match up with this specific set of values, then they are wrong, i.e. not right. Not that you would particularly care, of course. From your perspective, you only want to maximize your own values and no others. If your values don't match up with the values defined as moral, so much for morality. But you still should be moral because should, as it's defined here, refers to a specific set of terminal values - the one we labeled "right."
(Note: I'm using the term should exactly as EY uses it, unlike in my previous comments in these threads. In my terms, should=should_human and on the assumption that you, XiXiDu, don't care about the terminal values defined as right, should_XiXiDu =/= should)
I'm getting the impression that nobody here actually disagrees but that some people are expressing themselves in a very complicated way.
I parse your comment to mean that the definition of moral is a set of terminal values of some agents and should is the term that they use to designate instrumental actions that do serve that goal?
In You Provably Can't Trust Yourself, Eliezer tried to figured out why his audience didn't understand his meta-ethics sequence even after they had followed him through philosophy of language and quantum physics. Meta-ethics is my specialty, and I can't figure out what Eliezer's meta-ethical position is. And at least at this point, professionals like Robin Hanson and Toby Ord couldn't figure it out, either.
Part of the problem is that because Eliezer has gotten little value from professional philosophy, he writes about morality in a highly idiosyncratic way, using terms that would require reading hundreds of posts to understand. I might understand Eliezer's meta-ethics better if he would just cough up his positions on standard meta-ethical debates like cognitivism, motivation, the sources of normativity, moral epistemology, and so on. Nick Beckstead recently told me he thinks Eliezer's meta-ethical views are similar to those of Michael Smith, but I'm not seeing it.
If you think you can help me (and others) understand Eliezer's meta-ethical theory, please leave a comment!
Update: This comment by Richard Chappell made sense of Eliezer's meta-ethics for me.