Well, you know Isley... that is the point of the article... the disaffected groups aren't necessarily outsiders by their own choice but by the choice of the privileged or "in crowd".
As a member of a different minority I understand how derogatory terms, even when not meant in that way, can be offensive. In my day-to-day life I try to give people the benefit of the doubt and try to politely remind them that a given term is offensive and why.
That said, those of us who are not in a given population should not try and tell that group whether or not a term is offensive.