I have not yet seen the movie, but I would like to.
The fact that a character is named in the credits does not make him the subject of the movie.
Actually, if the movie had been made with Saladin as the subject, it would be infinitely more interesting, if no less controversial. But not as effective as propaganda.
The title of this movie itself is a triumph of propaganda, subtly implying clear equivalence between a murdering horde killing, pillaging and capturing slaves for their slave markets and for the Caliph, with Christianity.
That simply capitalizes on the abysmal ignorance of the average film viewer, most of whom don't have the intellectual means of separating reality from fantasy, or history from propaganda. For many, this movie represents history, with no qualifications whatsoever.
If this movie had been capitalized entirely by Saudi Arabia, it could not be a more effective means of pure, unadulterated propaganda.