I'm not sure how this is even a thing. I've never noticed someone only using black gifs or emojis as funny or exaggerated faces.
Here is a "warning" description for this video.
"Warning: This video contains historical footage of blackface minstrel shows which you may find offensive."
http://www.bbc.com/news/av/world-40931479/is-it-ok-to-use-black-emojis-and-gifs
What the hell is going on here? How can this even be stopped?