Again, although I agree completely, you seem to be missing the point.
The fact that most people presume does not constitute a fact that presumption is the only option. Thus the fact of the existence of presumption doesn’t negate logic as a viable option, it only implies a typical misuse. There wouldn’t be so much conflict on these issues if there was no misuse of logic. So the point is actually to get the logic straight void of presumption, not to presume presumption and thus presume defeat.
And it is the complexity of many situations that tempts presumption; “It is just too much trouble to figure all of this out, so let’s just presume…” or in the case of authority, “it is too much trouble to know the truth about the situation, so let’s just handle it this way…” But still such complexity does not negate a logical solution. It merely means that more honesty, patience, and scrutiny is required (the very essence and purpose of philosophy).
The ultimate foundation of logic and the escape from presumption is simply “the declared definition”. And that is why I first said, that any rational discussion can’t be made until a definition is provided.
In effect, we are trying to provide an ontological truth concerning “good” and “moral” that is coherent with physical reality. One cannot have an ontology, an understanding of existence, without declared definitions. Definitions are not physically objectively either right or wrong. They are declared for the sake of a chosen understanding, not to be altered within that ontology.
For example, to me this all a moot point already rationally resolved. In my RM:AO:Psychology, Sociology, and Economics, the word “good” and “of benefit” are defined as “maximal anentropic harmony” and is equivalent to the religious concept of the “Son of God” for mortal entities (“God” being defined as the ultimate determiner of what can or cannot happen). And with those definitions, rational decisions concerning morality can be rationally assessed such that the minimum amount of suffering and/or death occurs. And note that it is issue of minimal achievable, not absolute zero.
With such an understanding, there can be no ambiguity concerning morality. Morality can be objectively assessed even though subjectively amended. If one chooses to not define the relevant words in his chosen ontological understanding, he cannot resolve anything rationally and must merely bow to another and/or never be able to assess good from bad nor morality (which is why it is called “Rational Metaphysics”, RM, the very seed of the last enlightenment era).