Just to make it clear, I am white, so take my opinion on this with a grain of salt.
From what I understand, there isn’t a universal consensus among black communities that the n-word is okay between black people. Some people get just as offended no matter who says it.
Of course, some people are perfectly fine with it, but that doesn’t mean it isn’t a slur. It’s still a slur, it’s just not offending anyone at that moment. It’s like an empty gun: it won’t harm anyone, but it’s still a gun.
I mean, it might be a good excuse. Doesn’t change the slur.
In Blazing Saddles, the actors playing the racists apologised to their co-stars after every take. They had a damn good excuse to say what they said, but they still apologised for saying it.