Well, back when I was a kid in the late 50s and early 60s, keeping white people comfortable was the primary lesson black parents had to teach their children about white people.
This was only a few years after Emmett Till (which was not a singular case). For us, encountering a white person on the street was akin to stumbling upon a bear in the woods. The thing black parents already knew was that the Emmett Till incident had only displayed to the world that a white person could murder a black child and walk away from it. So, surviving an encounter with a white person was an exercise in keeping that white person comfortable while getting away.
Hmm. Well, keeping them comfortable is still "the speech" black parents have to teach their teenagers about surviving an encounter with the police, but at least today it's the police and not every white person. That's undeniable progress.
The "Magical Negro" trope has a lot of history in American media. It's essentially how the media began inserting black people when the general white audience was hostile to the concept. It goes back to Bill "Bojangles" Robinson in the 1935 movie
The Little Colonel, through
Casablanca, and goes up and beyond to Star Trek with Whoopi Goldberg as the "Guinan" character.
Here is a description of what it is with a lot of examples (Morgan Freeman appears often in the list for recent examples).
Here is a friendly conversation providing more detail:
There is also the similar "Magical Indian" trope.
But from the above link, there is also this interesting tidbit of how Rod Serling inverted the trope. I love trope inversions.
- The Twilight Zone (1985): Inverted in the episode "Paladin of the Lost Hour", which has a magical white man help the young black protagonist find his destiny. In the short story upon which the episode is based, author Harlan Ellison states, "One of these men was black, the other white" and refuses to say which one is which. Of course, for a visual medium, they had to make a choice, and it seems that they deliberately chose to avoid the Magical Negro trope.
Frankly, it's less of a thing now with more black people otherwise appearing in the media in roles with more different aspects than merely being a tool for the white protagonist to learn how to be a better person.
I was rather surprised to see a movie pointing it out and apparently satirically playing it up. That in itself could be interesting and funny, if done with the right satirical edge.
But the troubling situation in the trailer was that the young Magical Negro protagonist's plot struggle lies in his falling in love with a white girl. That's disappointing. It would have been more fun if the white guy our Magical Negro was helping had fallen in love with a black girl who was actually providing more support to the white guy without being magical...and our protagonist was also smitten with her.