There's a scene at the end of the movie where some whites are being attacked by a mob of blacks, many in blue Union uniforms with rifles and bayonets. (Hundred year old spoiler alert: they get rescued in the nick of time.) But modern audiences don't understand what kind of danger the women in the cabin were in, or what they might have done to escape it.
In Why ‘Birth of a Nation’ is still the most racist movie ever [NY Post, February 7, 2015] writer Lou Lumenick quotes film historian Thomas Doherty of Brandeis as saying [Emphasis added]
“I always have to explain to my students the scene at the end where the Northern soldiers are holding rifles over the heads of the women while they’re besieged by negroes trying to break into their cabin. The soldiers are prepared to bash the women’s brains out to save them from succumbing to lustful black males.’’Succumbing suggests seduction, but of course he means rape. In an article for the Hollywood Reporter, Doherty [Email him] makes this clearer:
So distant are today’s audiences from the racist conventions at the heart of the film that many of the pantomimed gestures and visual cures [sic] must be de-coded. During the famous ride to the rescue, the white men in the besieged cabin hold the butts of their rifles over the heads of the women — ready to bash their brains in rather than have their wives and daughters suffer "the fate worse than death" that was sexual violation by a black man.
Since the movie is in public domain, you can see the scene in question by scrolling forward to 2:55:00.
There is such a thing as a fate worse than death, though. Women who've been raped often commit suicide. The besieged whites in the film were not contemplating killing their wives and daughters to save them from impurity, like a Muslim who thinks his daughter has been having sex, but to save them from the horrible fate of being brutally raped to death—there are at least a hundred men in the attacking mob.
About the 14th ultimo, at a place called Hutt's Store, near the center of Westmoreland County, some of the negro troops went to the house of Private George, of Ninth Virginia Cavalry, and committed a rape upon his wife, who had just been confined with a babe only six weeks old. She is now almost a maniac, and begs that some one will kill her. [Major T. O. Chestney, July 5, 1864]That's something that actually happened, back in the 1860's, and scenes like it happen today, as we've reported here on VDARE.com with regard to the Pearcy Massacre, Knoxville Horror, Wichita Massacre and Winchester Atrocity—to name a number of crimes that never got any of the publicity that the death by justifiable homicide of Trayvon Martin did.
Apparently racially inflammatory movies involving white rapists are just fine.