In that explanation (same like Catholicism is in Christianity) I see divergent from the original teaching, due to simple reason as that would put a wrench in the gears of the aristocratic society.
The teachings of the Buddha was aimed solely at liberating sentient beings from suffering, your mentioned "middle path" is pulling out of the context of the original meaning of the middle path. In case of Buddhism middle path was referring to pushing own body to extremes in order to gain enlightenment. Budha was killing his own body in the process, which was prevent him to attain enlightenment.
Reason why your mentioned path is wrong it that along those lines one can arbitrary choose min and max limits of the function and choose the middle. So to give a very crud example "if murder is not ok, than acceptable number of murders is 0 and on the other end we have 8 billion people so middle is 4 billion?"
In same sense your version says that between slave and aristocrat there are many levels of gray, but in fact slaves are just a slaves and aristocrats are aristocrats, being in the game just helps aristocrats and prolongs the cycle of suffering.
Reason why your mentioned path is wrong it that along those lines one can arbitrary choose min and max limits of the function and choose the middle. So to give a very crud example "if murder is not ok, than acceptable number of murders is 0 and on the other end we have 8 billion people so middle is 4 billion?"
In same sense your version says that between slave and aristocrat there are many levels of gray, but in fact slaves are just a slaves and aristocrats are aristocrats, being in the game just helps aristocrats and prolongs the cycle of suffering.