You might know this already, but the original series in that universe, The Riftwar Saga, Feist wrote about a DnD campaign he played with his friends. I picked up the first one, Magician, and it felt just like a DnD campaign, so I looked it up and sure enough it was exactly that.
I'm making my way through all of the books and haven't gotten to the Krondor books, so I don't know how different they are as I could clearly see his growth as a writer in just the first series. I'm currently reading through the Daughter of the Empire series that he co-wrote with another author and I'm really enjoying it.
So which sense do we use to interpret the rules set out on how to get/treat slaves? How is that interpreted? Is it a metaphor? And how do you know which is which?
What it sounds like is you have lots of leeway to account for what you choose to believe is truth or fiction to fit your needs at any given moment. And if you're not sure what, if any, is literally true, how do you know there's a god at all? And you're defending Catholicism, which is in for an even more uphill battle than most because it's been around longer and has to account for all the beliefs that have had to be updated as knowledge and culture had changed.