Because any semi-intelligent narrator would make me a civilian. He'll think that people see me as a gangster and thus it would surprise them if I were a civilian
This way the semi-intelligent narrator will give an advantage to the gangsters.
If an intelligent narrator makes you a gangster, he/she will also assume that most of the players won't be smart enough to think about a potential trap and they'll still vote for you anyway, thinking you're a gangster.
In this case that intelligent narrator will help the civilians.
