An impasse?

No. You have already acknowledged there are scientists who can, and do, believe in evolution, but reject the notion of evolved morality. Why do you persist in making claims that are in direct contradiction to your previous statements?

I am prepared to accept that there are such scientists. I am not prepared to accept that they are right.

Is the power of flight "natural?" I'm sure you will agree with me that, yes, it is. But can you fly? I find your definition for what is "natural" (that it must "apply everywhere") to be quite peculiar. Certainly, it is at great variance with the way in which most biologists would apply the term.

I am a biologist. Flight has evolved in many different families of animals. Just like certain moral frameworks.

I'm sure you're much more knowledgeable about anthropology than I. However, you may want to reconsider your placement of Ramapithecus in the family tree of homo sapiens. At the very least, there seems to be a lack of consensus among scientists where Ramapithecus is concerned:

It was a deliberate choice, as Ramapithecus is a great ape ancestor, and we see clear evidence of moral behaviour similar to ours in the great apes.

I feel we are at an impasse. Even if one does not assume that morality is not something that has been subject to evolution (which I find a rather bizarre viewpoint, considering the evidence obtained from studying animal behaviour), there is still no basis to claim it is objective and universal.