Every game, and mod, has a set of goals, the ideals that lead the design. Some developers might prefer realism: I've seen an Europa Universalis III mod that especifically focused on bringing realism over any other consideration. It was not more enjoyable than the base game, but it was different enough to merit some gameplays. Some developers might prefer cutesy: games that focus on feelings as if they were artistic works. I'm thinking on Journey.
Here, the motu is 'balance'. It's explicitly said in the mod's name. We focus on balance, but at the same time we don't forget that the game still needs to be enjoyable, and if not realistic (there are too many abstractions in a game of this scale), at least some care to plausability is there. Maybe you missed all the long discussions, but things like Oracle giving a temple because, well, it was a temple in real life, comes from the historical knowledge of our developers and testers, and if you stop to look at this, the game is full of historical references, more accurate than what the base game was.
I agree that policies are designed to encourage some play styles, but I don't think this is a bad thing. I actually improved a lot my play style when I dip into Authority style. The lessons I learned in this policy tree can still be used with the others. For example, I almost never demanded tributes with the other trees. Now I know that even Tradition benefits from extorting a city state or two, just not that much as Authority.
Civ IV mods might be more focused on 'roleplaying', which is fine. Sometimes I want to play a good RPG game, sometimes I want a chess match, sometimes I just want to see a movie.