One of my hispanic buddies/co-worker calls me "white boy" all of the time. I like it and think it's funny but I just wouldn't feel right doing it back to him or another person of color for this very reason. If(IF) DL actually said this it wasn't just buddy buddy, it was malicious.Words and phrases have both denotative and connotative meanings. If you don't understand this, you don't understand language. If you try to pretend that connotative meanings don't exist, you're perpetuating a fraud on yourself.
Sometimes denotative meanings are much stronger than connotative. Sometimes connotative meanings are stronger than denotative. It depends on the context. But this phrase that Lindsey is accused of saying is clearly one in which the connotative meaning overpowers the denotative.
In the context in which it was said to have been spoken it would connotatively convey something like, "Slavery never really ended. I (as a white man) have the power to do whatever I want with you (as a black man). So you'll shut up and do what you're told."