Black people's faces obviously reflect less light. This is a much bigger problem for the cheap computer cameras that are not very good at collecting light. The software probably could not distinguish his facial features because there was less contrast due to the lower light.
Nonsense, if that were the case we'd heard about it by now. Also, the face tracking algorithms can already operate in far less optimal conditions than the one presented here so in _this_ case it shouldn't be a problem.
Forgetting that the algorithm was tuned to a specific color range however seems like an entirely plausible scenario.
