Buzzfeed attempts to pinpoint the pejorative use of "basic" to Klymaxx's "Meeting in the Ladies Room," which dates back to 1985. When people discuss the origins and use of "basic," they tend to ignore its historical racial implications, as I understand them. The race issue at hand is not just a matter of "black people use this term that white people have now co-opted," but that, like the word "ghetto," "basic" is historically coded to describe black people who behave in ways perceived to be "very black." And if "basic" is being used as an insult, then it means "too black," and implies that being "too black" is undesirable.
Anyway, that's just what I gathered from Joshua Gamson's 2005 biography The Fabulous Sylvester, in this description of disco diva/drag queen Sylvester's backup singers, Izora Rhodes and Martha Wash (aka Two Tons o' Fun aka the Weather Girls):
"Martha and Izora, and that kind of black, that's what I call basic black," Sylvester's friend Yvette Flunder says. "Cornbread and black-eyed peas. That's the kind of black folds that he liked being around. He was very basic black and for real, like his mama, and he had no shame about being a black man. He's a fried-fish, fried-chicken person. You'd do with quiche and pate, and he'd have you eating fried chicken."