You make a lot of excellent points, but I’m not too enthusiastic about what you do with them. You have promoted many of your opinions to the level of axioms without much explanation or justification, and then gone on to derive theorems based on same.
To pick on one conclusion, you decide that since we can’t know either the original reason or the survival effect of a “superstition”, we have no reason to call it “irrational” or to treat it as inferior to our best judgement based on science and logic. This may be true in some cases, specifically when the science is inadequate and the natural resistance of superstition to reevaluation prevents reckless abandonment of a bias that has been protecting us from “tail” troubles. But the science can improve, whereas the superstition cannot; and the regular reevaluation of the “rational decision”, while annoying and resource-costly, allows for improvement. One does not continue to debate the advisability of brushing one’s teeth daily, but one did have to be convinced of this at some point, or one would have just stopped as soon as one’s parents were no longer enforcing it. (Some do.)
Every system of “morality” (behavioral codes immune to reexamination) is an opportunity for cynical manipulators to “play the system” to their advantage. This is quite obvious in the various defenses of Free Market Capitalism. How carefully have you examined your own motives?