@Jungerheld: That's a complicated question. This could be an answer: The only reason why God allows sin is, because (despite Amoris Laetitia) we can always do something against it, and by doing so, we even "benefit from sin". So if there are cases when we don't counteract sin, either by believing that it is impossible or by denying the existence of it, then, clearly, we have in some way or the other allowed the devil to deceive us.