The trailer for the project -- released Wednesday -- has done little to assuage that furor.
"Urban Myths" tells a series of stories, including a fabled one in which Jackson, Elizabeth Taylor (played by Stockard Channing) and Marlon Brando (played by Brian Cox) supposedly took a cross-country road trip after 9/11.
The trailer has Twitter beside itself.
"The most disrespectful thing I've ever seen" one person tweeted.
In a 1993 interview with Oprah Winfrey, Jackson rejected the idea of having a white actor portray him onscreen. Winfrey had asked him about reports that he wanted Pepsi to cast a white actor to play him as a child in a commercial.
"That is so stupid," Jackson said. "That's the most ridiculous, horrifying story I've ever heard. It's crazy."
The film is not a biopic, he exclaimed, and said "It's Michael in his last days when, I have to say, he did look quite frankly rather differently than when we grew up with him in the '80s or earlier."
"The decision with the casting and the producers -- I wrangled with it, I was confused and shocked at what might come my way, and I knew the sensitivity, especially to Michael's fans and to Michael's family," Fiennes said. "It doesn't negate who he was."