Slavery was built into the constitution. The slave states - New Hampshire, Massachusetts, Connecticut, New York, New Jersey, Pennsylvania, Delaware, and Maryland made sure of that. Oh, and the states of Virginia, North Carolina, South Carolina, and Georgia too.
You might say that in 1861 the Deep South was motivated by a desire to preserve the Constitution.
Only if you were exceptionally stupid or biased or deceptive.
Racial equality? Is that now the standard for judging people who lived in the 1800s?
Maybe "racial equality" isn't the right word, but Dickens, who showed great compassion and love of justice in some cases had some real blind spots. He shared an anti-democratic streak with Thomas Carlyle, and that probably surprises a lot of people now who are familiar with his most famous works.