Yeah, I feel the same way. Fortunately, this particular secret is not hard to figure out once you know it's there, several LWers have done so already. Knowing your work on LW, I would expect you of all people to solve it in about 30 seconds. That's assuming you already understand UDT, indirect normativity, and Roko's basilisk. If you don't, it's easy to find explanations online. If you understand the prerequisites but are still stumped, PM me and I'll explain.
I think I've found a new argument, which I'll call X, against Paul Christiano's "indirect normativity" approach to FAI goals. I just discussed X with Paul, who agreed that it's serious.
This post won't describe X in detail because it's based on basilisks, which are a forbidden topic on LW, and I respect Eliezer's requests despite sometimes disagreeing with them. If you understand Paul's idea and understand basilisks, figuring out X should take you about five minutes (there's only one obvious way to combine the two ideas), so you might as well do it now. If you decide to discuss X here, please try to follow the spirit of LW policy.
In conclusion, I'd like to ask Eliezer to rethink his position on secrecy. If more LWers understood basilisks, somebody might have come up with X earlier.