I didn't claim to know the answer, just that your claims lacked support.
Of course slavery shaped American history, and thus its culture, but step back and imagine it never happened. Let's say the first blacks arrived in the US in 1990.
I'd still expect a similar level of racism toward blacks, because that's true globally. Even people in somewhere like rural China who have never met a black person are likely to look down on them.
Some of the Southern goofiness would be gone like you point out, but overall I'd unfortunately expect a remarkable similar situation.