Why I liked this movie.
Really, it isn't that bad. So long as you go in knowing what you're going into, the movie is entertaining, though probably only by those who are familiar with the first. I will detail what I mean below.
I've been trying to pin down what it is that they hate so much and it seems to boil down with a problem with the plot, jump scares, and the ending. While I also abhor jump scares used excessively, in this case forming most of the scary/startling moments, I also understand that a horror movie can be about more than simple adrenaline. The horror in this movie is the atmosphere, the feeling of confinement, regardless of the space, and an utter lack of a sanctuary.
It isn't a shock fest, there's no stupid upside down chick barfing, there's no finger breaking, there's not even an actual exorcism. Which brings me to the primary problem ---
This movie is not about an exorcism. Really, that is one of the biggest problems. The title makes no sense with regards to the content, and it suffers because of it.
Anyway, the point is that this movie is misunderstood and poorly named. Yes, it is a sequel to the first in the sense that the subject of possession is the same, but the story it tells is not really a sequel, but more of a complimentary piece to The Last Exorcism.
The Last Exorcism was a movie about a man finding his faith. The Last Exorcism Part 2 is about a woman who loses hers. Yet both involve the story of a protagonist coming full circle, accepting themselves, and choosing their own path. Rather than making the second film run parallel to the first, it moves away from it like a fork in the road. Two characters, both in search of a purpose, who find it, but take wildly different paths.
Cotton goes from a man so disenfranchised by his former beliefs that he openly exploited the faith of those who did, to a man willing to sacrifice himself based upon them. During the movie, he connects with the innocence and purity of Nell, and through her rediscovers his faith in humanity and sacrifices his own to save hers. His life, so devoid of purpose prior to the events of the film, comes together, is given profound meaning in his sacrifice driven solely by his desire to protect an innocent life.
Nell journeys from listless insecurity, to a purpose driven apotheosis of sorts. Driven away from humanity through loss and the ultimate betrayal, she finds herself unable to make the sacrifice Cotton made in the first. Where he acted for the sake of humanity, in large part thanks to his connection with her, Nell finds herself unable to do the same.
Honestly, who can blame her. Everyone she trusted betrayed her, other than Cotton I suppose, and in this movie it seems everyone not associated with the demon wants to kill her because of it. She put total trust in the group at the end of the movie and they responded by trying to kill her. Live as a lion, or die a lamb. Whether or not she made the right choice is all a matter of perspective, but it stands in stark contrast to the one made by Cotton.