Well, when I was avidly reading all the Agatha Christie our library had, it was first called Ten Little Indians, then And Then There Were None. This is the first I've ever heard of the former title.
As far as PC goes, words like n*%%^# are offensive and hurtful, esp. to my son-in-law who is from Antigua and, as a far as my daughter and I are concerned, for their twin boys.
I understand the historical context and agree with you ddw as far as Twain goes. And, I loved to hear my grandma read Little Black Sambo, but sometimes, I believe, we need to let go, even of pieces which may make us nostalgic. Yes, we can use them to educate; yes, it is important for people to remember; but, that does not mean we should use those terms in our common dialogue, as a sort of backlash against the extreme pc-ness which has come about. There needs to be a balance.
Just think, please, for one moment, how an African American might feel if they happened upon one of these postings, without the context of others? Or if someone Asian, visiting the Mudcat for the first time, saw the thread about the old "Chinee" man. Yes, later they may understand the historical context in which these may be presented, IF they ever come back after seeing such things.
Sorry, I for one, believe we need to respect one another enough NOT to use such terms and to move on to new and more enlightened ways of communicating. Preserve the old songs with derogatory words, use them in reenactments and in other educational settings, if need be, but let's not bash all things PC...some are worthwhile and life-affirming.