Room - Exploitation or serious work about violence against women?

Brie Larson no doubt deserved an Oscar for her performance in the Emma Donoghue production Room, but is it a good movie? Definitely a compelling movie, at least for the first half. The first hour of the movie is entirely shot within the "room" (a garden shed") in which Larson has been held captive for 7 years (she's now 24), held by an evil, horrendous middle-aged man, unemployed, living in a working-class Akron neighborhood; during her captivity she has given birth to the young boy who nearly steals the show, he's now 5, and will play a key role in her escape. Honestly, I didn't think I'd get through the first hour - not that the movie was bad in any way it was just too disturbing. From the moment I heard about Donoghue's novel I knew it would be compelling but wondered why the hell anyone would want to write about such torture (wondered the same thing about the over-praised Lovely Bones, which turned into a terrible movie). Examination of humanity at its lowest pitch, or exploitation ripped from headlines? Well - not much of a spoiler here - but they do get free, and I think most will agree w/ me that the 2nd half of the movie, with the mother and son struggling with adjustment to the world (which he had never seen except a "flat world" on TV) and to family, etc., is a let-down - the air has been sucked out of the movie, and out of us, already. In a way, the movie is a stunt - and I'm sure many would say it was a writer's concoction and could never happen - except that it did happen, and I wonder how much the book and movie were influenced by the horrendous Cleveland kidnapping story (the Ohio setting seems intended to make that connection for us). Part of me wants to consign this movie to the category of art about violence against women that weirdly titillates and sensationalizes the violence it purports to oppose - Dragon Tattoo being the prime example of that -- but I recognize that the motives were more sincere and the goals were higher in this film; it's not a crime movie so much as a study in personality and culture (thankfully, after mother and son are freed and we learn in passing of the arrest of the madman, we don't hear from him again). We can admire this movie for its ambitions and its technical prowess, but it's a damned hard movie to watch, or to like.