"The second is there seems no prohibition on black people using it and not only using it in passing but to positively offend each other. It's a funny old world. "
Not funny at all. It's about intent, context, and to an extent "owning" the word. Black people aren't calling each other or themselves n______ to be offensive -- not to themselves, at least. Calling a black person a such-and-such to their face when you aren't either black or their friend will get you in a heap of trouble because either you're trying to be offensive or you haven't shown that you aren't being.
I'd have thought that the idea that words have a meaning based on who says them, when, where and to whom isn't exactly a difficult one to get. Rather like when David Lammy referred to "posh white people", everyone on AB got, if not offended, then certainly angry especially about the "white" part. With some good reason, I might add -- but to then act surprised when black people might also be upset about being described as "you black [insult]", or "you N", is the height of hypocrisy.
As I say, I don't for a second believe that Anne Morris was trying to be offensive. It's an error of judgement and she should pay the consequences of that error of judgement. Whether that amounts to having the whip permanently withdrawn I don't know, but it's the lack of judgement that is the issue here.