Richard Holloway, in 'Godless Morality', argues that "ritual practice" is not the same as "ethical principle." As an example, he argues that the practice of refraining from eating pork in Muslim and Jewish religious cultures is not per se an ethical action, merely the instantiation of an ethical principle which is keeping a promise to one's god. Thus, to eat pork, the ethical principle broken would be that of breaking a promise; the eating of pork itself would not be unethical, as the proscription of pork was merely a historical/sociological/anthropological/geographical accidentality.
Clearly there are many ways to break a promise, but only one ethical principle for each 'set' of manifestations of it (following Holloway's theory).
The above is, at any rate, the way I have tried to explain it to my grade 12 (last year of high school) Philosophy students.
Does this explanation hold, and what are the problems with it? (I am presuming it is problematic because, although it appears convincing, I am still...