I agree in part, but let me say something on behalf of The Color Purple in particular: The sister who becomes a missionary in Africa writes back in realization: I thought I was going home to 'my people' ... these are not my people... they sold us. The don't care about us, they don't love us, they don't want us back... they sold us!
I personally was very happy to see someone acknowledge this. Moreoever, Alice Walker is one of the main discoverers of and champions of Zora Neale Hurston, who was muscled out of the African American literary world by Langston Hughes and the other Marxist black separatists because she was essentially a Republican. If you read Their Eyes Were Watching God, there is very little of the evil white man in it once the days of slavery are over. It's just blacks among other blacks living their lives, and is very interesting.
Nevertheless, students also need copious doses of sophisticated writing to model their own writing on, you are right. I just wanted to throw that opinion in there.