People who do not have dark skin make a system. It turns out that the system performs poorly on people with dark skin, and possibly causes discriminatory outcomes.
Perhaps the training data didn't have enough dark-skinned people. Or perhaps the optics and sensors didn't work well.
The point is that the outcome is biased against a certain group of people, and it's (edit: partly) because that affected group of people lacks representation in the group of people developing the system (edit: , because if they were represented they would have flagged the issue and it would have all been presented and handled differently).
No, it does not imply that the individual researchers are racist as such.