LOL the saintess is a stupid asshole.
Let's admit that god is benevolent, and that it actually had a long acting plan and a good reason for for the oracle. Either it want to rule directly sending oracles to the saintess, otherwise even a theocracy need to be managed. In case her blind ideology go way further then what her god probably intended.
Also a benevolent god may be represented by a not so benevolent church, depending on how and how much they can interact with their priests and how they can communicate an oracle, as if god cannot communicate often and clearly (but need to rely on metaphors, figurative speech and so on) the church can develop a doctrine on it's own. For example the saintess speech where she say the dukes wield political power as a form of god's assigned privilege, and should wield it directly and absolutly (absolute monarchy) while Rudell's "reign without rule" may indicate he was working, or wanted to work, on a costitutional monarchy with elective system (like UK or Japan itself).
Also we don't know wethever the oracle god, the skill maker god and the god who reincarnated him are the same god.
However Rudell, as a reincarnated person, should know the risk of letting a religious take material hold of a state, yet he choose to comply. A shit move if he actually cared about his people. With the amount of support he is shown to have, there was a lot other ways he could have acted. Even with the idea of slow life, it was the worst choice to take.