Great book. I first read it about forty years ago, just after I'd read about his mucker Tom Sawyer, another great literary work.
So what's the problem?
Some dolt has decided that the word 'nigger' should be replaced with the word slave. I think we all know why.
Relativism at it's worst. The whole point of the book is that Finn, who is a racist, in a racists state discovers enlightenment. It's like trying to re-write the New Testament and leaving out the word Christ.
So, should we leave writings from over a hundred years ago alone and see them in the context of when they were written or, like the Ministry of Truth, re-write them to suit modern sensibilities?
"He who controls the present, controls the past. He who controls the past, controls the future." -- George Orwell