Here’s how it goes down:
Do you want to teach various creation myths and explanatory myths? That stuff goes into cultural anthropology, or if there’s enough of it, such as Hellenic mythology, then a literature class, but then it’s cross referenced with the values of the age. No-one wants their modern religion taught as mythology right next to others that are regarded as ancient superstition.
Do you want to teach existential questions and morality? Awesome! We have entire school departments dedicated to philosophy. Typically 101 is an intro to existentialism and 102 is an intro into morality. And both of them move beyond religion in the very first chapter. The thing is, religions assert their positions on why are we here? and are property rights evil by mere assertion. Ministries say we have the authority, and you obey. and might even back their position up by scripture. But none of this really answers either why or how we know and even Descartes (a devout follower of the Church) couldn’t find a sufficient answer to his own evil demon except to assume by God is good by default (rather than God being a construct by which a corrupt Church might manipulate their flock). Religion turns out to be a starting point for our purpose, the point of everything and right and wrong, but where we end up after the enlightenment is far beyond the apologists.
I don’t even know what the basics of christianity are anymore. Do you teach it is a monotheistic religion or a polytheistic religion that changed its mind. Do you teach it as them believing humanity stemmed from adam and eve, or adam and eve were the first christians and their 3 sons were to spread the beliefs but acknowledge that humans already existed on earth created by other gods/means. You break bread and it is literally the body of a man, or figuratively. 40,000 versions of christianity that found reasons to not be the same sects. So I suppose you teach a historical touching of how it has changed but by no means could you teach the concepts of Jesus before highschool without upsetting parents these days, even then. Imagine the response to forgiving all drug users, imprisonment being wrong, not having any spending money, etc. Angry parents pissed off claiming schools are teaching Jesus was “some sort of communist.” Was banking not against christian law as well, as you could not ask for interest and such as a true christian would have given it to you without expectation?