In my opinion, there are two possible reasons.
First, the government probably does not think these guys are any kind of a threat to them. I mean, so what if there are some people out walking around when no one knows they're there? It's like the thing about the tree falling in the forest with no one around.
Okay, I know this. It has to be "The fact that Northern opinions of slavery can be hypocritical"
The author wanted to have people see themselves in Miss Ophelia so that they could reconsider their views on slavery.
I hope this helps some! :)
Not cry? we're on the threshold of death soon we shall be inside so it is (B)