Oklahoma here, we definitely learned about it too.

But take like the Tulsa Race Massacre. I grew up hearing it called the Tulsa Race Riots, but I don't recall ever being taught about it in school, I heard about it from my parents. I still didn't really know much about it until several years ago. I literally grew up in Tulsa lol.

Edit: not to say I believe the story. But I think it's possible. I heard about the Massacre from my stepmom, who did a paper on it in college (mid 80s), and apparently had trouble finding a lot of different source material at the library.