2) People know that field slavery was bad but think household slavery was pretty all right, if not an outright sweet deal
"These were house slaves, so they must have had a pretty all right life, right?" is a phrase I heard again and again. Folks would ask me if members of the enslaved household staff felt "fortunate" that they "got to" sleep in the house or "got to" serve a politically powerful owner.
Relatedly, many guests seemed to think that the only reason to seek liberation from household slavery was if you were being beaten or abused. A large part of the house tours I gave was narratives of men and women who dared to attempt escape from it, and so many museum visitors asked me, in all earnestness and surprise, why those men and women tried to escape: "They lived in a nice house here, and they weren't being beaten. Do we know why they wanted to leave?" These folks were seeing the evil of slavery primarily as a function of the physical environment and the behavior of individual slaveowners, not as inherent to the system itself.
It is worth mentioning that I never, on any tour, said the slaves weren't being beaten -- these visitors simply assumed it. It is also worth mentioning here that the bulk of wanted ads placed in newspapers for fugitive slaves are for house servants, not field workers. Apparently whatever slavery was like in the big house, people were willing to risk their lives to get away from it.