Many things are naturally repulsive, but are indulged out of necessity or gain. For instance Aristotle wasn't opposed to slavery, yet nonetheless in his writings, now some 2400+ years ago, he found himself obligated to lay out an extensive and lengthy defense and rationalization of such, and he even predicted what would eventually end it:
"For if every instrument could accomplish its own work, obeying or anticipating the will of others, like the statues of Daedalus, or the tripods of Hephaestus, which, says the poet, 'Of their own accord entered the assembly of the Gods.' If, in like manner, the shuttle would weave and the plectrum touch the lyre without a hand to guide them, chief workmen would not want servants, nor masters slaves." [1]
There were millennia of efforts to end slavery, but it's only the technological and industrial revolution that finally succeeded in doing so. But the point is that even though Aristotle was ostensibly not opposed to slavery, he nonetheless knew it was a decision that needed justification because it was fundamentally repulsive, even in a society where it was ubiquitous and relatively non-controversial, thousands of years ago.
This 'natural repulsion' is, I think, some degree of evidence for persistent, if not absolute, morality throughout at least thousands of years of humanity's existence, and I see no reason to assume it would not trend back long further than that.
[1] - https://classics.mit.edu/Aristotle/politics.mb.txt