You can't have a country whose economic foundation was slavery not have a cultural problem.
You might want to review history. At the time the US was founded, slavery was legal and practised in nearly every other country in the world. (And historically, slavery was almost never about race per se, just different social/cultural/economic groups. Islamic holders of Christian slaves, for example.)
That doesn't make it right, but it does mean you're full of shit. (Or perhaps you have a point: the west African nations whose economic foundation was selling those slaves also have cultural problems. Or perhaps the cultural problems came first.)
But slavery was everywhere, since the dawn of agriculture (those fields aren't going to work themselves). It was the Industrial Revolution which made it economically unviable -- which is why it died out in the northern, industrial states sooner than in the southern largely agricultural ones, and in Europe before it did in the New World.