I always felt Dee Jay was a little problematic as a character, he was a caribbean stereotype even though he is supposed to be jamaican, but that's another can of worms, representing him as a monkey should be self explanatory on why it's bad.
Mr. Sand Man is a powerful boxer, he has powerful punches, you know who also has powerful punches? Little mac, someone from his own series, I don't know if it's against the rules but hell you could even use Bowser or any other heavy, but you go with donkey kong? That's just bad.
And Villager has a ton of skins, like a ton, why would the dark skinned one when thievery is involved.
In the end I feel like I didn't add a lot to the conversation it's just hurtful to me. Not only gaming is full of "heated moments" and stuff like twitch chat's racist copypastas and spams, having a major dev on a famous and fun game doing this is kind of alienating.