Mr. Messenger:
The word you are so adamantly claiming is a double standard, if you understand black history in America, which most people from other countries don't understand, is that the initial usage of the words stemmed from the brutality of slavery in the American South, and this derogatory term was used as a symbol of oppressive resentment during the highly racist times of slavery and civil inequity. It has a very bad connotation with what hangings or "lynchings" as Americans call it, which was the mob-murder of black people.
People should be aware of the socially repressive roots the word has. Now it is liberally used because popular culture has embraced through hip-hop music in a different way, but it has an awful history.
What do Aussies call aborigines? Are there derogatory terms for them? What if the derogatory terms they use were suddenly embraced by a popular culture as meaning "friend" and white Australians say it commonly. Does that seem far fetched? I bet it does, but that is a similar situation.
This is a touchy subject, and the word has a bad connotational history, I think people should read about the history and why non-Americans (myself included) may not grasp it and how to better understand other peoples' history.
Sincerely,
God