Bull!@#$.
It's a way to remove a Lord from his Lordship. It is, in fact, the only way to do that besides banning him. That is an incredibly powerful action in this game.
Powerful for who? The duke of said region. That's the sole person who can take advantage of this feature. If he wants to replace said lord. If he's the duke himself, or supports the lord, it's utterly pointless, because the duke will just reappoint the guy. This feature gives nothing to the religion of the priest doing it, it just causes the loss of followers and exposes the priest to arrest. Negative gain. The only person who can benefit from this feature is the duke of the target, and as such it's a pointless feature for religions. It doesn't even harm the region or offer deterrents to just reinstating the guy.
