"To Kill a Mockingbird" was often on the exam syllabus, certainly till I retired a few years ago. I remember the shock shown by Y11 at the n word, but they accepted that it was part and parcel of the book.
The n word was proscribed, surely, because of the deep offence it caused to black people? Wasn't it from the vocabulary of the slave owners?
I do think we need to be sensitive about using offensive words, of course. But I think the censoring of historical works is not useful. Was it Dr Johnson who changed to ending of "King Lear"? Or did he just deplore it?
(Slight digression - equally, I remember Y7 getting very cross because someone's father, in a novel set in the fifties, actually smoked!!)