I don't think it is a coincidence that African-American actors are being given awards for portraying stereotypical images (immoral, oversexed, uneducated). But when they pick up that script and decide to accept the role, they assume culpability as well. Angela Bassett turned down the role in monsters ball for obvious reasons. Monique, may or may not have understood the implications when she decided to play in that poverty porno film called "Precious".
On one hand she could have interpreted it as most uninformed misguided consumers did as "telling an untold story". You know, the same excuse rappers use to justify most of the filth they represent. On the other hand she might not have seen anything wrong with it just as the other stereotypical characters in early american films such as Mammy played by Hattie Mcdaniel in Gone with the Wind or Mantan Moreland of the 30s and 40s. So that leaves us with the fundamental question did they know any better?
This isn't anymore about movie executives out to perpetuate negative stereotypes about black people, any more than it is about an american appetite for sickness and how we'll sell our souls and the dignity of our people for 15 minutes of fame. Yeah, the american public might get a kick out of the 2009 sequel to the "Color Purple" but it's because in this society there will always be a demand for ignorance.