I think the biggest hole in the theory you have put forward is the idea that Moral Law somehow enables us to avoid conflict, or directs us to a place where ‘everyone likes us’. I think that the exact opposite is often the case. If we were concerned with simply pleasing other members of mankind, I think we would adopt a more ‘relative’ moral theology, as much of the secular world has. That makes much less conflict because there is no bedrock principles on which that morality stands.
Our Moral Law does not change to please others. We cannot make certain things permissible simply because they are popular. Likewise we cannot compromise truth because it is convenient. Look to any number of the Saints for confirmation of that fact, many of whom suffered enormous pains and trials rather than commit a sin, or deny truth.
If our beliefs were simply an invention of mankind created to ensure we ‘get along’ with the rest of the world I think it would be much more lax and fluid to change to every whim or notion, adaptable to allow anything… no matter how amoral or horrifying.
But, thank heavens, we do not see these qualities in our Moral Law. It is not subject to the whims and desires of mankind. Instead it is a solid bedrock. Unchanging. A standard by which we can measure ourselves and our lives. As all measuring tools, it is a constant. Just as one inch is always a fixed length, as is a yard, as is a mile. Can you imagine how strange the world would be if everyone suddenly decided to create their own standards for measurement? One fellow would say “My inch is 8 centimeters”. Another would say “My inch is the length of my arm”. Another “My inch is the distance between two fingers”.
How then would we ever know the correct length to cut a piece of wood?
We must look to something outside ourselves and our own idea of what an inch is. We look to an authoritative standard. The same is true of many things. We do not set our watches by what time we personally ‘think’ it is. Instead we go to an outside standard to ensure we have the correct time.
In the same manner, we have the moral law, by which we can hold ourselves and our behavior to an unchanging authoritative standard.