To me it's all about the audience and the intent and purpose.
It is bullshit to say a man, black or otherwise, can't dance a certain way or act a certain way for any reason. The whole point of freedom is to allow a person to be themselves without judgment.
So if someone is genuinely into whatever they are doing it is fine. Coonery would be purposefully doing something for the entertainment of the white man and knowing they were laughing AT you or your expense and not genuinely into whatever it was that you are doing.
It's the ultimate contradiction that other races can do silly songs/dances, etc. but yet you come down on a black artist for being silly.
Of course this is all my opinion and it's a tough subject to address. I think Bamboozles and Chappelle are the best things to look into to understand the complexity of it all, outside of you know, books and shit.