Yeah, it is hard for the modern mind to grasp it. It was indeed a different time, and a suffocating world at that.
I don't know, one can only guess at these things… but history has indeed left some clues.
The antebellum South, as everyone knows, was an hierarchical society. The duel quo duel, then, was a reserve of the elite. They saw themselves as somehow inhabiting a higher level of civilization, having a more refined and delicate sense of honor than lower levels of society.
But more importantly, "honor" was reputation. Period. It was also a world associated with shame rather than guilt. The code of honor defined who they were and where they belonged in the ordered ranks of society. And it was the opinion of others that determined that rank. Thus, for example, they feared being perceived as weak or inferior, which was a deadly combination in a stratified society based on slavery.
Again, the main goal was to avoid shame. How others saw them was more important than how they felt about themselves privately. It was really that simple— what drove them to dueling fields. Their delicate sense of honor was so fragile that they truly felt they could be wronged by mere words and acts, and that written laws could never remedy such things because they were mere categories that could never take cognition of honor and dignity. This forced them into ritual acts.
So, it didn't really matter whether one was right or the other person wrong in terms of libel or slander. Being successful or unsuccessful in a duel did not settle that issue. What was settled was your reputation in the eyes of others and thus your rank in society.
Again, avoiding shame from your peers— and that mindset went beyond dueling.
Recall Mary Chestnut description of a conversation that is typical of this mindset. She noted this exchange toward the end of the war:
"Are you like Aunt Mary? Would you be happier if all the men in the family were killed?' To our amazement, quiet Miss C took up the cudgels-nobly. 'Yes, if their life disgraced them. There are worse things in life than death."