It is my understanding that the individual card rulings on Gatherer are essentially clarifying comments. i.e. they are "just" an application of the comprehensive rules to that specific card.
With that in mind, the rulings for Carrionette state:
A creature with Protection from Creatures can’t be targeted by this card’s ability.
But, when Carrionette is in the graveyard, it is not a creature. My guess is that rule 112 covers this somehow, but I'm not seeing it.