Not only is this blatantly wrong, but you're insinuating that people of color are incapable of using scientific reasoning [the use of their brains] to come to the conclusion on what shape Earth is.
What reasoning could you possibly use to determine the shape of the earth?
Unless you do specific experiments to test for curvature or you go out to space and look back at the earth, there is no conclusive way to know the earth's shape.
If you believe the earth is round, you only believe it cause someone else said so.