Once you unwind past evolution and true morality isn't likely to contain [...]

I think either a word has been missed out here, or and should be then.

If I recall correctly, I did ask myself that, and sort of waved my hands mentally and said, "It just seems like one of the best guesses - I mean, I don't know that people are valuable, but I can't think of what else could be."

I find this fairly ominous, since that handwaved belief happens to be my current belief: that conscious states are the only things of (intrinsic) value: since only those conscious states can contain affirmations or denials that whatever they're experiencing has value.