I read the novel before I saw the movie. The novel does gloss over how bad slavery was for the slaves. I read somewhere that before the movie was released they made changes to make the movie less objectionable from the standpoint of black civil rights activists.
The novel's author was born after the Civil War but grew up hearing the attitudes of white Southerners to the War between the States and to Reconstruction.
I'd agree with that, but it is a great soap opera and even soap opera can rise to the level of great art (well, filmmaking).
And yes, it does paint the antebellum South, at least the Georgia plantation version of it, in a very positive light.