Things they forgot to tell you.
In November 1526, African slaves in South Carolina rebelled, killed masters and ran away to the Native Americans. Does that sound like they were happy in slavery?
The Whig Party collasped because of black/white issues. This prompted the formation of the Republican Party.
In 1866, a Civil Rights bill was passed by the Republicans over a veto from President Andrew Johnson.
The race issue prompted the realignment of the Democratic party of 1964-72, and the south went from democratic to a republican stronghold.
The Black/White relationship was the basic cause of the Civil War. Some want to down play that issue under the guise of holding the union together. However, that was particially true, but the reason that the union was splitting was the black/white issue.
There were other major American events connected to the race issue: The Alamo, Seminole Wars, the expulsion of the Mormans from Missouri, reconstruction, and the lack of equal rights for African Americans..
Perhaps the GOP (Grand Ole Party) has few African Americans is due to the history of its formation, eh?