I like Brooke's voice and many of her performance and I certainly feel that justice has not been done with her being voted out.
As Kat 5309 says, she shouldn't be penalised simply because she's trying to spread goodness rather the so called dark side. ya, sure everybody has a dark side but does it do any good to show the whole world your dark side and further influence the next generation into a misconception that dark is cool and sexy and what people like? No. It will further promote hatred, not something we need now!
And as much as I like watching American Idol and all the superb performance by some of the greatest talents in the world, I think the voting system doesn't do justice to the real talents in the show. However, this is not really a talent competition after all but rather, it is an idol competition of who has a bigger fan base.