Controversial, uncomfortable, but not exploitive
The Savage Is Loose in my opinion, even though very uncomfortable and squeamish with the subject matter, was not exploitive. It felt like a sexual psychologist was behind the making of the movie.
The premise is that we humans need sexual companionship from the opposite sex as a matter of biology. Deprived of sexual fulfillment with the oppositie sex can lead to emotional and psychological instability and neuroses, at least that's the idea I perceived.
The husband and wife had each other. But the son, reaching maturity and beginning to feel the powerful physical urges of sexual longing, had no one of the opposite gender. There was only his mother, who per chance in the movie still looks rather attractive for her age. Everyone knows just how powerful sexual urges are in young men to the point of craving. In the normal world, the son would quickly hook up with some pretty girl in his high school. But here he was thrust into an artificial situation.
I think the movie ended on a good, if not happy note. Tragedy is narrowly averted, but there is no solution specified for the son. Really, the only true solution would be for all three to be rescued as quickly as possible.
Other posters have been instrospective about the subject matter as well. The mother was faced with an agonizing dilemna or imbroglio, for which there was no happy choice of outcome. A mother normally would do anything, sacrifice anything, to ensure the health, the well-being, the very life of her child. What about this situation? She understands the sexual torment torturing her son. Does she do the unthinkable to quench his need? Will that even help him at all or harm him permanently. The movie could have dealt further with subject.
If I had to do a remake, one possible different path - you might call it a cop-out or equally squeamish - would be to make the mother NOT the son's biological mother. In other words the story could have been that the biological mother died while the son was in infancy. The father quickly remarried and the new wife adoringly raised the baby boy as if he were hers. So the story line would still be on the squeamish side, but at least avoiding the really truly cringing, appalling issue of biological incest. In other words, my change of storyline would have more possibilities left open to pursue. The second wife could also be significantly younger than the first wife, maybe five to eight years or so which allows the explanation why she is still so attractive. Now, as the director of a remake I could really lead the audience into the edge of gross-out-ness at the scene where the mother and son confront each other physically. Just as the audience is starting to squirm, the mother tells the son, 'I've loved you all your life as much as if I had given birth to you myself'. Then the audience would gasp and realize she is not his biological mother. The son already knew that, but we, the audience didn't know that until that moment.