The argument used to be that it was not so much what was said, but the context in which it was said and the meaning that was attached. However, it�s moved on apace.
White people are now deemed to be inherently racist by definition. Furthermore it is only they that can be racist. Therefore if any of these terms are used by them it can only be in a derogatory, disrespectful, racist fashion. These views, which have been held for some time in some quarters, were amply aided and abetted by the ridiculous McPherson report into the handling by the police of the death of Stephen Lawrence. This was the report that coined the phrase �institutional racism� (which set the Metropolitan Police Service back twenty years) and deemed that a racist incident is one which is perceived to be racist by the victim or any other person [whether connected with the incident or not].
So the context now no longer matters so long as the terms are uttered by a white person (as was demonstrated when the Prince of Wales used one of them to refer to one of his friends). There are plenty of uninvolved third party activists ready to take offence on behalf of somebody else who may or may not be offended themselves.
In contrast, non-white people, of course cannot under any circumstances be capable of racist thoughts or deeds, so the use of these terms by them is perfectly acceptable.