Little bit of context behind your situation I guess. The word in question, "nigga", was used as a racial slang to put down people with black skin, therefore it is a negatively geared word created for the sole purpose of putting down someone for the color of their skin. However your argument is, you yourself, a person with black skin, are not offended when someone may call you a nigga or when you use it, but are you arguing that you yourself, hold the common opinion of all people on this earth with black skin? No, you can't, you don't have the right to decide for others whose families were subjected to slavery, harassment and prejudice under that word, about how they feel when someone says "nigga". Using the term in a social space, is racism, because the people who have to read it or hear it, may have been prejudiced by that word all their life, so even if you don't take offence, they do, and it is a put down.
So in short, just because you don't take offence to that, doesn't mean others don't, KZG is a community with many different cultural backgrounds and you need to be mindful of their cultural beliefs and reservations, it's called respect. This may be the internet but if you can't respect others just because they aren't physically in front of you, then I suggest you grow up and stop hiding behind your screen thinking there will be no consequences, because it is cowardly, crude and honestly disgusting. However if you do respect others on the internet, then I apologize for those words, but I hope you understand now why the use of that term is not permitted, as we try our best to accommodate everyone on our servers