Thank you for the kind words! I'm happy you enjoyed it!
Actually each buildings has an influence on houses. Cathedral has 10 000 and Church has 2 000. this influence is divided by the number of houses in the building zone. (you can see your cult influence and the other cult influence when you hover a house).
In your case your cathedral didn't have enough influence on houses to counter the influence of the 3 red churches around. ;)
Part of the "end game" is to manage this influence ratio.
I should have made something so the player understand this mechanic better...