I believe they way it works is that FDT tells you to make the bad decision (here: suicide) if faced with the actual situation, but the argument is that you won’t get into the situation at all or less often because you’re playing FDT.
By the time you find yourself facing the problem in which FDT recommends killing yourself something’s already gone wrong, because the situation ought to be prevented by playing FDT in the first place.
But of course the question always is: should you actually find yourself in the decision problem, despite being an FDT-agent that ought to never get here, should you still follow FDT?
I’d argue the answer is “lol no” but I believe the argument in favor is to assume you’re just “hypothetical you”, evaluating the situation without having to bear the cost. E.g. you’re just a simulated version omega spon up to check how you’d react in this decision, not “actual you” who’s faced with the decision. After all “actual you” is not supposed to even get into the situation. If you truly believe that, then chances are you’re not you, because that’d mean omega is wrong, which is extremely unlikely.
I though the answer was “assume you’re simulated and follow FDT to save real-you the trouble of ever getting into this situation in real life”. Out of the all arguments to take the bomb this is the only one I’ve ever heard which I can at least understand where it’s coming from.
If that is not the FDT response then, I guess I don’t know why you’d ever really blow yourself up. I did read the whole post, including rereading the example against just now.
But what I got from it was mostly the insight that FDT kind of answers a different question than CDT, in that it’s goal is to shape what situations you end up in, not necessarily how to get the best result out of a given situation.