But... does writers don't know that innocent doesn't mean dumb ?
Let's take as example a son touching his mom's butt. The innocent mother will understand that there's potential sexual intent behind it, but think that her son is just "at this age", and just try to know what it feel to touch a girl butt. She'll fail to understand that her son can feel a sexual desire over her, because she's too innocence to imagine such a thing.
This while the average "dumb mom" in game tend to think that he searched to take the glass on the table and just missed it by five meters ; or thing that his hands are cold and he just want to warm them. She'll fail to imagine just one second that it can possibly be some kind of indirect sexual act. It's no more innocence at this level.