I haven't seen Jennifer's Body (and I'm a huge baby about horror films, so I may not see it), but I've noticed the critics and reviewers - often but not exclusively male critics and reviewers - often have difficulty with movies that dig deeply into the female experience, which it sounds like Jennifer's Body does. It's probably partly sexism, but I think it's also because the story shape can become so different than a narrative that fits the male-dominated mode that viewers find it straight-up hard to process. They've got a particular slot in their brain they want to put this story in and it just doesn't fit and they throw up their hands and cry "This is such a bad telling of X type of story!" - when really it's not X type of story at all, so of course it doesn't fit.