Books to Movies: Can a Movie with a Message Avoid Letting the Message Take Over?

Yes.

For A-Z List G, I reference Charlotte Perkins Gilman. I tackle one of Gilman's rather preachy texts in my tribute/critique His in Herland: Astyanax in Hiding. Herland starts out as good story before devolving into a series of lectures about the "good" society. I postulate that dogma is a problem of most utopia fiction. 

On the other hand, Gilman's most famous short story, "The Yellow Wallpaper" is all show-no-tell. It is quite a remarkable piece, yet it has a strong message. So what spares it the lecturing tone? 

It all comes down to the narrator. As with far-too-complicated graphic novels, "The Yellow Wallpaper" avoids the "information dump" problem by confining all the understood action to the narrator's point of view. 

A film, naturally, can step outside first-person or limited third-person narration. H.G. Well's War of the World is a remarkable piece of writing since the reader is held to the narrator's point of view. The classic movie can't help itself: it resorts to aerial "big picture" shots.  

Perhaps because it is a domestic story, the 1989 PBS version of "The Yellow Wallpaper" manages to stick to the narrator, as she goes slowly crazy. And it works! The story may have a message but it is primarily a horror story anyway. Extra hints regarding the husband and his colleague and their views of female "hysteria" make Gilman's point but they are subtly presented and only as far as the narrator overhears them. 

Message never takes over. Story runs the piece. Consequently, the message is stronger. The viewer is drawn into the circumstances, not set up to have a "proper" reaction. 

Leaving the viewer's agency intact is always the best choice.