I honestly don't think that I need to explain why "Black man style English" is a terrible way to describe a pattern of speech/accent. And while I know that these things don't come from a place of racism or ugliness...can you not? It's 2015 and although SK is far from being a melting pot, somebody had to think that this was a bad idea.
I mentioned this in the video, but I'm not trying to throw Rap Monster under the bus...just using him as an example. BTS fans don't hurt me plz <3