If you look at it anthropologically, every civilization from every era on earth, separated by time and location, has had some code of conduct which dictated what was good behavior and what was bad.
Some were more comprehensive than others, but still strikingly similiar to one another. What you must ask yourself is why that is.
I believe it is because of our soul–our link to God, as being made in his image–that gives us an almost intrinsic, unlearned knowledge of good and evil. Like an artist’s signature on a work of art; there’s a small piece of himself in his work. It’s the little “Made in Heaven” sticker on our souls.
It’s that little bit of God’s light that we recognize inside of us; a wee bit of revelation of Himself. If we nurture that small glimpse of God, it can hopefully unfold to a much more profound knowledge of God.
That’s not to say that if left alone in a vacuum a completely segregated people will develope Catholicism, all I’m saying is that it’s possible to know at least a little about God in a complete social vacuum. The natural Law everyone senses inside of them can attest to this.
Those that will never hear the gospel through mere unfortunate circumstance will not be judged on that basis but on their fidelity to the intrinsic Natural Law.
But in lieu of all this, one fact remains that it is our obligation as being human and gifted with intellect to pursue a more complete knowledge of our creator, to not remain complacent in our ignorance, counting on that ignorance to save us.
I’m not sure if that answers your question, but I hope it gives you a better understanding at least.