You are correct that not everything can be said, even about a public figure, such as threats.

RPF/RPS is not a threat. It is creative writing. It does not advocate violence. It does not post home addresses or names of people's children. It is fiction.

And by the way, that recent LJ story about someone being visited by the Secret Service for her post about Bush? That was fiction, too. The story was subsequently proved to be a hoax.

Let me reiterate: RPF is fiction.