You’re speaking of “Universal Conscience” which is the capacity for deep moral reasoning and a sense of right and wrong across diverse societies.
Theres also a difference between Subjective and Objective morality. What’s more plausible, that the vast majority of the roughly 8.3 billion people (that’s wild to think of in scope by the way) came to the same conclusion that adultery is really bad despite human nature of wanting to have sex with as many beautiful people as possible OR that through the centuries we’ve adopted values stressed on us through biblical teachings and we are viewed as reflections of being created in God's image ("imago Dei"). (Or at least strive to be)
People take it too personal when they say people outside the Christian faith can’t make decisions we feel are just and right BUT like I said…where’d you get that barometer of just and right? Directly or indirectly it’s all through God.