> The idea of teaching some sort of “secular” ethics has never made sense to me …

An intro ethics class won't shy away from religion, it comes up a lot. You'll most likely even discuss differences in different sects of Christianity. You should also have the discussion of if morals are universal (and if so, which ones) or are all made up.

Secular just means you discuss more than one viewpoint. The idea of teaching morality from only one perspective never made sense to me. You won't even get that limited viewpoint in Seminary school, even though it'll certainly be far more biased