That's one way to look at it --
You can either look at it as a slang term for a "black person", which became derogatory with the passage of time,
Or you can re-cast the word to mean "gangster", "someone with a dark mind", etc. -- after all, most people don't have an urge to call Alan Keyes a "nigger". He is rational, educated, an upstanding citizen, etc.
I know there are blacks in the (traditional) Catholic priesthood (and currently one black seminarian in the SSPX seminary, if I'm not mistaken), and those are certainly not deserving of ANY derogatory term, even if the term was a technical description at one time.
I've learned not to use the term, just like swear words, but I think if I were forced to use the term, I would only consider using it with gangsters, hoodlums, criminals, etc. After all, that is the group that uses the term to refer to themselves!
Matthew