Consider the success of Uncle Tom's Cabin, the runaway best selling novel, turned into an extremely popular play. Clearly many Northerners did have sympathy with the slaves. Many more probably didn't think about them much at all.
You overcomplicate. The South produced 72% of the total value of trade with Europe. The vast bulk of that money ended up in the hands of New York and Washington DC.
You try to obfuscate by making it complex. It's not. It's very simple.
Doesn't provide evidence.
I provide evidence all the d@mn time. You just ignore or reject it because it's not to your liking.
Makes things up.
Like what? I don't make up anything. Show an example of where I have made something up.
Doesn't consider anything that doesn't support what he already believes.
Doesn't buy your flimsy arguments which try to cover up the economic data that is clearly visible.
Consider the success of Uncle Tom's Cabin, the runaway best selling novel, turned into an extremely popular play. Clearly many Northerners did have sympathy with the slaves.
It is unquestionable that propaganda works. Over time with the correct stimulus you can steer the public. We saw the effect of "I don't want to die!" movie helping to abolish capitol punishment. We saw the book, "One flew over the coo coo's nest" help to get rid of asylums. We've witnessed how Upton Sinclair's "The Jungle" helped institute government control of the meat packing industry, and how "To Kill A Mockingbird" created sympathy for black people who were then viewed as getting unfair treatment by the legal system in place in the South.
Yes, Harriet Beecher Stowe (Liberal progressive activist from Hartford Connecticut) created the 1860s version of "woke" activism, and which even President Lincoln acknowledged was a strong contributing factor to triggering the Civil War. He jokingly said something to the effect "So you are the little woman who started this war."
But in the absence of such influence, the dominant sentiment in the North was a hatred of blacks and a desire to keep them away from whites.
Many more probably didn't think about them much at all.
Eventually they were all made to think what the government wanted them to think. Arresting people who disagree tends to have that effect. We see something similar with all the government mandated vaccine activism.
Ask yourself this: what class of people at the time had the money or the leisure time to buy novels or go to the theater? How does that class compare to those advancing racist theories today to oppress their political rivals?
Many more probably didn't think about them much at all.
If true, those would have been the farming people raising families of many children (pre-birth control) and the small tradespeople who supported the local region. The U.S. population was majority agrarian until 1939.
However, I disagree with your premise. There were no radios, tv or internet, and even railroads were largely limited to distributing product locally; but there were newspapers; people all over the country may have had little opinion about slavery per se, but many opinions about who would move in to their community, and whether they would be compatible neighbors.
There was no such thing as "cool", "casual" or "indifferent" attitudes towards strangers in those days when the vast majority of all the American people, including children, worked up to 12 hours a day, six days a week, and there was no welfare. Even 3/4ths of a century after the CW, my own illiterate Irish-American grandfather went to work at age 7 on a waterfront and worked for the same company to age 65. Every individual and all they brought with them either enhanced the community or dragged it down; so the prospect of a dispersal of former slaves was indeed a large concern.
The "do-gooders" (like today's progressives) dreaming of an immediate and successful integration of the two different cultures (African-slave vs European-American) were concentrated in small areas of big cities and near the Ivy colleges (Yale, Harvard) or elite old churches in New England. Their uopian fantasies worked about as well as George W. Bush's assurance that the Middle Easterners would embrace democracy if we just went over there and got rid of a few overlords.