After all, Hollywood has almost always been dishonest and cowardly when approaching the subject of slavery.
Take, for example, the very first Hollywood feature film ever made: D.W. Griffith's sad, shameful The Birth of a Nation. This was an outrageously racist film that depicted African American men as stupid and as extremely sexually aggressive towards white women. The film also glorified the Ku Klux Klan.
Hollywood's other big blockbuster set in the slavery era, Gone With the Wind, was hardly much better. This was a film that glamorized the old Deep South. Slaves were shown happily singing, laughing, dancing and enjoying a colorful agrarian lifestyle. It was a grotesque distortion of the realities of slavery.
In reducing the horrors of slavery to mere entertainment, Tarantino is carrying on a sad tradition for Hollywood (and indeed American society in general) in refusing to honestly confront America's own Holocaust. It would be impossible to imagine, say, Germany making a similar film about the Jewish Holocaust.
I can hear the Tarantino defenders already, though. "But it's just entertainment!" they'll say. The problem is that slavery is simply too horrific a crime to be the topic of a movie made for mere entertainment (particularly coming from a white film director). White America has never honestly confronted this horrific crime.
If Hollywood is to ever properly tackle the slavery era, it needs to do so with a respectful, dignified Schindler's List type film (preferably made by an African-American director). What we don't need is an profane, cartoonish, overrated Tarantino ripoff of a Sergio Leone film.