If morality were axiomatic, then worldwide we would have a collective shared understanding of what is right or wrong, immutable over time. That’s clearly not the case.
It’s the divvying up of ingroup and out group that tend to create disagreements in morality. I.e. we understand forgiveness, but we disagree who is worthy. We understand justice but we disagree who deserves punishment or why.
That tends to make a pretty big difference in results and conclusions.