This makes a lot of sense. People (human, anthropomorphic animal, or other) have cognitive dissonance, which often takes a lot of time (and sometimes therapy) to recognize and resolve. It's why we see others often behave in contradicting manners, sometimes even when religion is concerned.
I always interpreted Sam's behavior as a sign of this, given his belief in a wrathful God and belief in the possibility of redemption. These two ideas seemingly contradict one another and result in Sam's elevated levels of emotional distress, as seen through his anger, guilt and anxiety. Until he enters into a psychological state of congruence (which he most likely won't due to all the uncertainties regarding God in general), these emotions and behavioral contradictions will persist. Of course, Sam doesn't view it this way. He views all of his difficulties and the resulting emotions through the lens of Sin and Virtue, which is a form of all-or-nothing thinking. He is trapped within the rigidity of his own beliefs.
This turned out to be a lengthier response than I intended, but I do personally relate to Sam a lot and that is why I love him as a character. I didn't grow up going to Mass regularly, but I somehow still managed to have The Catholic Guilt© for many years. Even to this day, I have a bit of a guilty conscience. I see a lot of my old self in Sam and that's why I love his perspective.