African American Achievement Gap

Through the year I never understood why their remains to be such a huge achievement gap when comparing African American to the rest of the White population. I believe I know what the problem is and it starts in elementary school.
Once most African Americans hit 3rd grade they start to learn African American history from teachers who tell the story of Black being descendants of slaves. They tell our children that Blacks were freed by Abraham Lincoln via the Emancipation Proclamation. And the story pretty much stops there. No in depth story that will in steal pride in African America children.
How this affect Black children is simple. It teaches inferiority in the Black children as they only hear that they were slaves and freed by a White man. Nothing about the civil war and how slaves fought in their own freedom. While at the same time teaching Black children that they are inferior it teaches White children that they are superior for the same reasons.
I ask why do elementary school aged children need to know this? We can surely teach children about history without creating inferiority. Nothing has changed when it comes to the achievement gap because teachers are still peddling the same lessons from the same biased history books.