I have a distinct memory of buying my wife a present one night back in 2004 (I can't remember the occasion), stopping off at a nearby bar for a quick beer before heading home, and seeing on the overhead TV a news report about a pregnant woman named Bobbie Jo Stinnett who had been murdered, and had her baby cut from her womb, by a walking nightmare named Lisa Montgomery. Other than the kind of nebulous horror that we all feel when we learn about new ways in which human beings torture and destroy each other, I don't remember any of the thoughts that went through my mind, but I do know that at no point did I think, "Boy, I sure hope somebody makes a movie about this some day."
Ah, but that's why I don't get paid to make horror films, because apparently two people thought that very thing, and not only that, but they took the job upon themselves. I do not blame Alexandre Bustillo or Julien Maury (both directed, and Bustillo wrote the script) for making a film based on the Stinnett murder (or any other murder like it -- I don't actually know that the Stinnett killing was their specific inspiration, but obviously it was based on the actual existence of this type of crime). I'm a horror fan, and while my tastes in the genre don't typically run in this direction, the philosophy of approaching horror by examining genuine, Earth-bound abominations like this is a valid one. I can think of few things more grotesque and awful than what happened to Stinnett, and while I suppose the idea that there is any conceivable merit (it should be noted here that the use of the word "merit" in regards to the horror genre is frequently different from its use in any other context, but it still applies) in constructing a work of fiction out of that story is debatable, an argument in favor of the existence of a movie like Inside -- or like Inside in theory, rather than in actual fact -- can be made. Basically, if a work of art can deal almost exclusively with an act of madness and evil, and find the humanity of the victim, if not the evil (though if you can do both, more power to you), then the existence of that work of art is justified and valuable.