But religions cannot choose their priests... They can choose their full members at most.
Let me give an example: Sir Kepler joins a religion, and is made a full member (not really to hard, and it is almost impossible to filter possible problematic nobles without seriously spoiling the fun of everyone that wants to try the religion game). He goes to a level 3 temple and from then on starts influencing peasants whenever he can, so as to drop the amount of followers of the religion. Heck, he can even be calming them, and claim to be making a service to the realm. And what can the religion do about that? Would that be a case for the titans? He can have perfectly good IC reasons to do it...