...sounds mostly good so far. Except that there's plenty of justification for thinking about morality besides "it's something we happen to think about". They're just... well... there's no other way to put this... perfectly valid, moving, compelling, heartwarming, moral justifications. They're actually better justifications than being compelled by some sort of ineffable transcendent compellingness stuff - if I've got to respond to something, those are just the sort of (logical) facts I'd want to respond to! (I think this may be the part Roko still doesn't get.) Also, the "lucky causal history" isn't luck at all, of course.

It's also quite possible that human beings, from time to time, are talking about different subject matters when they have what looks like a moral disagreement; but this is a rather drastic assumption to make in our current state of ignorance, and I feel that a sort of courtesy should be extended, to the extent of hearing out each other's arguments and proceeding on the assumption that we actually are disagreeing about something.