I don't think you really understand the point here and I don't think you're factoring in the context of it either.
They 1. Made a character who isn't black, black, and normally that isn't really that big of a deal, unless you 2. go out of your way to make this character as stereotypical as possible in the few scenes they have. Which is exactly what happened.
The thing about stereotypes is that some of them have a real origin, but it doesn't mean you should be building a damn character around them for the sake of comedy. There is also a difference between showing a black character watching BET in their leisure, and having a black character risk their life and be offered a sole personal freedom and choose something extremely stereotypical as their reward instead of something sensical. I mean, maybe even if they showed him in his cell watching a regular music video or a sitcom from BET it would have been less cringey. But you know what he was watching in his cell?
Twerking asses. If they wanted him to say something funny there were a million other things he could have asked for.
We can't be this forgiving with this stereotype shit.
I don't know if it's better or worse that they showed they knew how to write black people in a non-ridiculous fashion with Deadshot and Waller. Then again those characters weren't supposed to be the comic relief, and that's usually where the stereotypical shit comes in.
I guess I can be happy that he was barely in the damn movie so I didn't have to see him or hear his bullshit through the entire stream of feces.
I'm not usually one to jump of the "PC" train, but damn I have my limits.