These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Possibly Justified in that the entire movie is a retelling from Olive's perspective.
Also, several snide remarks in the movie imply that many who hate the Christian group are Christians themselves - the group is hated for being obnoxious and for doing Activist Fundamentalist Antics, not for being Christian.
Anvilicious / Author Tract: It is easy to see the film as having a strong Anti-Christian bent; the antagonists are loudly Christian, and Olive's attempt to see their perspective lead her straight into her enemy's lair or into an empty room where no one listens. This largely depends on the viewer's appraisal of the film; see the above entry.
Amanda Bynes' character is a clean-cut, Holier Than Thou Christian fundamentalist. Since this movie, Bynes has become better known for her drunk driving charges, traffic accidents, disgusting and disturbing Twitter rants, and generally bizarre behavior than she is for her acting. The fact that this was the last film she did before her sudden meltdown doesn't help matters. It makes her "seems as if someone's going on a downward spiral" quote more painfully ironic.
Hollywood Homely: Subverted. Olive speaks about her lack of allure, being invisible to members of the opposite sex, and how she has never been the sexual desire of anybody, which would come off as hard to believe given Emma Stone's beauty, but the eventual point of the movie is that it all revolves around image and perception. She was never supposed to be physically unattractive, just viewed that way as a result of her High School status.
Iron Woobie: Olive definitely qualifies. At one point in the film, her fellow students, including her erstwhile best friend are picketing at school with placards calling her a whore, and she still keeps her head up. And when she tells Mrs. Griffith "I could have chlamydia," you want to give her a hug and stand up and salute her. It Makes Sense in Context.
Les Yay: Marianne frequently comes across as a repressed lesbian who is attracted to Olive. At one point she actually sniffed Olive's hair.
Men Are the Expendable Gender: Olive is threatened with expulsion for cussing, while Brandon, who she sees leaving the Principle's office before she enters it, and who has a bloody nose as the implied result of a fight, is merely told to "sort it out". If you're a boy, nobody cares.
Brandon, Olive's friend who is bullied for being gay. His "We can talk about how things will get better all night long, but right now this sucks!" speech was especially heartbreaking in light of the multiple gay teen suicides around the time the movie came out (fall 2010). He gets his happy ending though.
By about halfway through the movie, Olive herself. In the attempted rape and confessional scenes, you just want to reach through the screen, give her a hug, and tell her it'll all be okay.