"Words can take on associations,..."

Yes, Kevin...they can, but 'nigger' was always meant to be demeaning, and there was no middle ground. It is nowhere NEAR 'retarded', which was meant simply to refer to those with 'diminished capacity'. I'd suspect that folks using 'retard' as a pejorative term caused others to react to ANY form of the word. Remember when someone used 'niggardly' in a commentary a few years ago? and horrified screeches arose from those who could not cope with the fact of that word having a NON-derogatory meaning?

Words do not go out and grab meanings....people (often the ignorant ones)imbue them with meanings beyond their original ones

"Mongol" was always a bad choice and a de jure insult to a race.

"How kind of Bill"..kindness has nothing to do with it. I know better than to USE the word in most contexts, for the reasons noted above. I am simply **noting** my opinion that it is NOT in the category of certain other words. I do not appreciate being forced to scan & censor my own vocabulary unnecessarily to conform to gratuitous changes.