There are several black inventors. Carver was one for example, as was the guy that invented the self oiler for trains (”The Real McCoy”)
I have worked with and studied with several very intelligent African Americans. One was, as I used to joke with him “A higher breed of cat” than my old farm boy roots are.
To say they are to stupid, is stupid.
It can be argued that you are correct but that those individuals mentioned are outliers, exceptions to the norm