The significance of this quote is that Huck is sort of telling us what the values are of the society in which he lives. He is telling us that abolitionists were looked down on in that time and place. He does not really like the idea of being seen in this way.
This is important for the book because one of the main themes is how Huck tends to go against the societal values of his time and place. Even though people will think of him in this way, he is going to end up doing what he thinks is right.
When Huck asks Jim how he got to Jackson’s Island, Jim tells Huck that he has "run off." Initially, Huck is surprised that Jim has committed a serious crime, but Jim quickly reminds Huck that he promised he wouldn't tell anyone. Huck then says that he won't say a word and comments,
"People would call me a low-down Abolitionist and despise me for keeping mum—but that don’t make no difference" (Twain 45).
As was mentioned in the previous post, this statement is significant because it illuminates the beliefs and views of Huck's society. Huck grows up in a society where slavery is commonplace and the hatred for abolitionists is evident. However, Huck's comment also suggests that he is an outcast with his own set of beliefs. His statement regarding not caring about what society thinks also foreshadows his decision to help Jim escape. Huck is an individual who inherently does not agree with society's perspective on slavery. This comment not only explains the beliefs of Huck's society but also introduces Huck's individuality.