Since Dickens saw very little of slavery, how could it be otherwise?
“Wars are rarely about the milk of human kindness and always about power, land or money.”
That’s true. Secesh didn’t just think blacks were inferior, they wanted to protect their wealth. Hence their reason to secede, and start a war to achieve that objective.
Their current wealth was just fine. Secession would have allowed them to keep more of it, 60% of which was getting grabbed by Washington DC (tariffs) and New York. (Excessive shipping costs, handling costs, insurance costs, warehousing costs, etc.)
You may not know this, but almost all of the export trade in cotton went through New York control. New York businesses completely ran the trade.