The Queen tells you that the building isn't in fact a church. A more accurate name would be a temple, as the religion Prospitians follow has little to do with Christ-like figures. You are told about a lot of things about the religion practiced by Prospitians. Unlike your earth religion, there aren't any holy days that the religion requires for Sabath. Instead, Prospit has the policy of shorter workdays every day, but tons of vacation days that can be taken on weekends or the Prospit equivalent or can be used on other things like actual vacationing.
Prospit, as mentioned before, worships the frog instead of the cross or star or what have you. The Frog is a symbol that, admittedly, is plastered in a lot of places, but isn't necessarily worshiped as the main prophet. Instead, the religion worships the book written by your friend, Syb. You know, the book that appeared about 700 pages ago. The one which JN picked up twice, yeah, that one. The Queen tells you that there has been no contact with the actual book, but the previous ARBITRARY DICTATOR (WHITE FRAIR), used his FENESTRATED WALL to come read over someone's shoulder as they read it, and he transcribed what he saw.
Now, you may point out that this seems very silly for an entire religion's text to be based on something one guy read through a window and rewrote from memory, but then again, all religious texts are a lot like this. The Bible is "the word of god through the ears of a few monks long long ago", and the origins of the rest of the texts all have similar, conceded stories that go along with them. You get to a place with a large stained-glass window.