Actually I have studied American history (particularly the Civil War) in great detail, but in this case I havent even mentioned American history, the US, or its creation. I'm talking large philosophical concepts. Yes I know Slavery in the US is all about economics, and immigration, and the needs of industrial versus agrarian societies, and where the line is drawn between federal power and state rights. What I am saying is that underlying all that is basic Human nature, most effectively illustrated in the Bible. I'm pretty sure that the overwhelming majority of southerners knew that the whole institution of slavery was immoral, and certainly contrary to the faith most of them professed, yet they continued with it anyway because of the incredible ability Humans have of simultaneously justifying contrary views if they think both are to their advantage.
You do not understand the American south.
Those who held slaves often justified it based on their faulty interpretation of the Bible. Most southerners were not slave holders. Some went to churches where they were told that the Africans were less than human.
Not understanding the founding of the US (which is no where covered in studying the civil war) leaves you at a disadvantage.
Your argument is overly simplistic