The slogan proposed by the Fourth Martial God was "Uphold the Law as if the Law Exists." It was meant to be a practical summation in response to an era where the "legal system" was completely destroyed, and "equality" and "justice" could not be found.
Of course, it must be clarified that the call to "Uphold the Law as if the Law Exists" is not demanding that heroes rigidly follow past laws in their actions. That would be highly unrealistic. "Law" refers to the procedural norms that are specified under certain specific conditions, according to some general rules. It is an expression of the will of the ruling class and a tool for state governance. In different times and places, the "legal provisions" themselves vary.
Only such progressive laws can cope with the constantly developing humanity.
It is illogical to demand that later generations abide by the laws of the past.