I do know that rural ("kuntree") Southern blacks masturbate the least, while suburban mid-Atlantic whites masturbate the most. For a few country southern blacks, masturbation isn't even a thought: as soon as they reach sexual awareness, they have sex, thus leading to the outrageous (pre-)teenage birth/abortion rates among the poor rural South.
Wow, cool! Though I don't know how you know this.
He is right however.
At first, until I reread that, I thought it was a racial stereotype. But it isn't: that makes perfect sense. They are the most poor, uneducated group in the U.S. This has little to do with race, and more to do with socioeconomic cultures.