Pierre Delacroix (whose real name is Peerless Dothan), is an uptight, Harvard University-educated black man, working for the television network CNS. At work, he has to endure torment from his boss Thomas Dunwitty, a tactless, boorish white man. Not only does Dunwitty use AAVE, and use the word "nigger" repeatedly in conversations, he also proudly proclaims that he is more black than Delacroix and that he can use nigger since he is married to a black woman and has two mixed-race children. Dunwitty frequently rejects Delacroix's scripts for television series that portray black people in positive, intelligent scenarios, dismissing them as "Cosby clones".
In an effort to escape his contract through being fired, Delacroix develops a minstrel show with the help of his personal assistant Sloane Hopkins. Mantan: The New Millennium Minstrel Show features black actors in blackface, extremely racist jokes and puns, and offensively stereotyped CGI-animated cartoons that caricature the leading stars of the new show. Delacroix and Hopkins recruit two impoverished street performers â Manray, named after American artist Man Ray, and Womack â to star in the show. While Womack is horrified when Delacroix tells him details about the show, Manray sees it as his big chance to become rich and famous for his tap-dancing skills.
To Delacroix's horror, not only does Dunwitty enthusiastically endorse the show, it also becomes hugely successful. As soon as the show premieres, Manray and Womack become big stars, while Delacroix, contrary to his original stated intent, defends the show as being satirical. Delacroix quickly embraces the show, his newfound fame and awards while Hopkins becomes horrified at the racist nightmare she has helped to unleash. Meanwhile, an underground, militant rap group called the Mau Maus, led by Hopkins' older brother Julius, becomes increasingly angry at the content of the show. Though they had earlier unsuccessfully auditioned for the program's live band position, the group plans to bring the show down using violence.
Eventually, Womack quits, fed up with the show and Manray's increasing ego. Manray and Hopkins grow closer, which angers Delacroix. When he attempts to sabotage their relationship, they only grow closer. Delacroix confronts Hopkins, and when she lashes back at him, he fires her. Then she shows him a videotape she created of racist footage culled from assorted media to shame Delacroix into stopping production of the show, but he refuses to watch it. After an argument with Delacroix, Manray realizes he is being exploited and defiantly announces that he will no longer wear blackface. He appears in front of the studio audience, who are all in blackface, during a TV taping and does his dance number in his regular clothing. The network executives immediately turn against Manray, and Dunwitty (who is also wearing blackface) fires him.
The Mau Maus kidnap Manray and announce his public execution via live webcast. The authorities work feverishly to track down the source of the internet feed, but Manray is nevertheless assassinated while doing his famous tap dancing. At his office, Delacroix (now in blackface make-up himself, mourning Manray's death) fantasizes that the various coon-themed antique collectibles in his office are staring him down and coming to life; in a rage, he destroys many of the racist collectibles. The police kill all the members of The Mau Maus except for a white member known as "One-Sixteenth Black", who tearfully proclaims that he is "black" and demands to die with the rest of his group.
Furious, Hopkins confronts Delacroix at gunpoint with her brother's revolver and demands that he play her tape. As the tape plays, Hopkins reminds him of the lives that were ruined because of his actions. Then Delacroix tries to get the gun from her, but is shot in the stomach. Hopkins, horrified, flees while proclaiming that it was Delacroix's own fault that he got shot. Delacroix, holding the gun in his hands to make his gunshot wound appear self-inflicted, watches the tape as he lies dying on the floor. The film concludes with a long montage of racially insensitive and demeaning clips of black characters from Hollywood films of the first half of the 20th century. After the montage, as the cameras point to Delacroix's dead body on the floor, the camera then shows Manray doing his last Mantan sequence on stage.

Question: Why does Dunwitty reject the work of Delacroix?
Answer: It is rejected because the potential series portrays black people in positive and intelligent scenarios. 
Alternative answer: He feels that they are "Cosby clones" due to his racism.