if she was sexually assaulted by a priest who broke his vows to God to remain celibate, you can understand why she might break her own vows to remain in cloister so as to escape an abusive environment that made her vulnerable to such a despoilment of her person
now taking her current state of mind in question: well if she was a nun who had committed herself to the Roman Catholic system, and that same system was corrupted in her eyes by the actions of a man she would have formerly held in esteem as an ambassador of that same Church, and moreover, in his position as an 'Alter Christus' or 'another Christ' of that same God she had made her vows to; to then have everything she believed in be shaken to its very foundation and taken away, would drive even the most functional person to despair
think of it, every paradigm she had based her life on would be shattered, and this seismic event would leave her in ruins; the confusion and the need to make sense of her experience readily making her susceptible to wild speculation
if the sexual assault also induced a psychotic reaction or prompted some schizotypal thought which is very common in survivors of rape, then it's no small wonder she now engages in conspiracy theories