A sincere question. 10 points to the best answer. Can you offer advice?

Being a human, I do not perceive dark skinned people as n i g g e r s but I see several posts mostly by trolls where dark skinned people are referred to by the forbidden n word. Being an educated citizen, I was brought up to believe that you should not discriminate anyone on the basis of caste, creed or race but the n word has become so common that I am wondering whether its still considered as a racist word or whether its a socially acceptable way of greeting the dark skinned people. I hear so many people referring to themselves by that word that I stand confused on whether I can address them that way. Could you please enlighten me on the subject and express your views regaring the same?