Complex sentence: Race is the supreme value of the religion and the Golden Rule of their socio-ethical system teaches that what is good for the White Race is the highest good, and what is bad for the White Race is the ultimate sin.
Split into simpler sentences: Race is the supreme value of the religion and the Golden Rule of their socio-ethical system teaches that what is good for the White Race is the highest good. Inversely, the religion teaches what is bad for the White Race is the ultimate sin.