science

This is the definition of "systemic rascism". These devices are the standard in hospitals and medical offices. They work optically, nobody bothered to check if the amount of melanin in skin affects them. Its likely that they were either tested entirely on light skinned people, or that the results for black test subjects were ignored or discarded as outliers. Nobody set out to make a device that might put black patients in danger, but nobody bothered to make sure it didn't.