Alright, so first off, this film needs to be discussed through the lens within which it was made. It's obviously difficult to watch it knowing it supported racism and subsequently lynching. However, it should be noted that the filmmaker D.W. Griffith was a relative liberal by the standards of the day and at this point in U.S. history, historical revisionism in regards to the Civil War and Reconstruction had taken hold with the prevailing view that carpetbaggers and politically enfranchised African-Americans were considered a negative result from the post-war policies. And it was being taught in schools as such. So D.W. Griffith was operating under the assumption that this was a majority view of the Civil War, which was fairly true and would have to have foreseen the shift in mindset coming in the future to have known he was supporting a viewpoint that would be on the wrong side of history. That being said, after receiving a backlash from many liberals around the country in response to the perceived support of the KKK and revisionist history towards the Civil War, Griffith felt so horrible about the mindset he contributed towards that he made Intolerance as a response, which was all about tolerance and loving your neighbor and even enemy.
To be fair to the non-historical view of this film, the way African-Americans are depicted is inherently ridiculous. The film completely vilifies them, especially at the end, when the Black soldiers parade through the town, and the black legislature is fighting and throwing shoes at each other as if they are inherently barbaric, and there is a heavy emphasis on them mixing with white women. There were a lot of black men throwing themselves at this one white woman to have her it was very over the top even considering the fact that most of the performances were over the top. It’s kind of scary that you could feel the hatred of a white man towards a black man sleeping with his “sort” of women through the lens of cinema, but that perspective shift is there. And you realize with this film that film is a powerful weapon. Even to me, with a hundred years of distance in lifetime from the setting, I still felt a sense of persuasion and propaganda towards the cause of the Ku Klux Klan through the filmmaking techniques that made me empathize with the characters.
And that's what's interesting is that from a storytelling perspective it was highly successful in creating a gripping, dramatic narrative with characters you cared about, at least from a structural standpoint, and followed on a journey. This film is a landmark achievement in the birth of narrative filmmaking with its inventive use of close ups and editing to construct emotional and intellectual associations with the narrative sequencing of images. By cutting from wide shots that show actions in their bare, stark nature, to close ups which provide emotional intimacy and a sense of closeness in understanding the characters, the viewer receives a holistic overview of the situation. Both the context and subtext. This was quite difficult to translate with earlier, "stage" style films that were forced to shoot scenarios mostly from a wide angle. The events unfold in a cold and detached manner so that you are more moved by the events themselves than by the performance of the actor and as a result their character.
Now that's where this gets tricky because as you identify with the characters from Birth of a Nation you are identifying with racists and confederates as well. In a way this film is propaganda. It was inciting deep seated racially motivated and politically motivated hatred. And as a result of the close ups and editing beats that could influence your emotional association with a character you felt more akin to them.
In this regard, the power of film became very apparent in how it could shake you. Birth of a Nation is a film that shakes you to your core and manipulates you to identify with characters you might otherwise hate and even find yourself subconsciously rooting for them. As humans, storytelling is programmed into us, even evolutionarily. We are made to respond to storytelling stimulus and have natural reaction trigger that cause us to root for or boo certain characters, and a lot of that is based off the sequencing of events and the perspective we're shown. And Birth of a Nation really creates this device in a very amazing way. The use of the multiple storylines was very unique in how tension is built from creating a ticking clock out of the necessity of one rescuer needing to arrive in time while cross-cutting to the individuals waiting to be rescued. Every time you cut back to the people waiting to be rescued your emotional investment in their survival is heightened. This is probably by far the most complex story and set of characters at this point in film history's development.
And like Intolerance, which follows we really see the grandiosity of movie making in terms of both production value and story concept. This film takes the notion of film being a portal to display "Other worldly creations" or "Larger than life" scenarios to its actualized potential. It starts to break the two dimensional barrier that the previous “stage” films had been working in.