Well, I think it’s more of a stereotype for Asians primarily because there are (at least where I’ve been) a lot more Asian professional immigrant families that fit this model than other groups. In my kids’ school, there were a couple of Africans who fit this model, but many more Asians. It may be different elsewhere, of course.
Plus, as far as I know, no African parent has written a highly publicized book touting this form of parenting, while an Asian parent did so.