No, it does not. By your logic, you could also say that it is stereotype to say that girls can’t have bowties . It’s simply trying to look too deep for actually pretty clear author’s intention that “girly things” does not mean anything.
Scenarists and authors, song writers and composers are the actual artists and they are often what Sarah described as artist. Many celebs are just performers who interprets what has been written for them. Unless you’re a public figure, you don’t always get the credits you deserve. Unless you’re a fanboy, you might not recognize or know who George R.R. Martin is, but likely to notice an actor from Game of Throne.
One step at a time.