What I claim is that morality is obviously the product of a combination of factors including (But not limited to) evolution, environment, genetics, reason, and learning, which we use in an attempt to maintain social cohesion and enhance survivability. We are able to evaluate the consequences of our actions with respect to specific goals, like the well-being of our fellow creatures, or the flourishing of human society, for example. Moral systems are data-driven, which is why they can depend on a situation and why they are subject to change, especially over time. In other words, we learn what works and what doesn't, act accordingly, or add to it based on evidence. This would explain why we find versions of morality everywhere within the animal kingdom and it also explains why moral values have changed over time. If you're worried that this is all subject to preference and opinion, it should be pointed out the the Christian system of obedience to authority is based on the preferences and opinions of the god you believe in. You just happen to think those opinions and preferences are more valid than those of the people who actually inhabit the reality in which we live.