Because banning books has always ended well, and has never been held up as an eternal symbol of a corrupt society...
Cory himself explains it perfectly over at BoingBoing: "I don't think this is a problem because my book is the greatest novel ever written and the kids will all miss out by not reading it, but because I think that the role of an educator is to encourage critical thinking and debate, and that this is a totally inappropriate way to address 'controversial' material in schools."
Little Brother is an absolutely exhilarating young adult novel about teens fighting back against Big Brother. Most of us read 1984 in school (and other dystopian classic, such as Brave New World), but Little Brother arms readers with the necessary knowledge to fight back. Big Brother is watching you, all right — but who's keeping tabs on Big Brother? The book is set vaguely now-ish, and even reading it as an adult, it was both educational, and horrifying. I'm glad I read it after the Boston Marathon Bombings, or else I would have been even more freaked out during that situation, rather than being oblivious to the other real-life horrors of what was going on (the basic plot of the novel follows a teen named Marcus Yallow who skips school to go LARPing, which puts him in the wrong place during a terrorist attack and leads him into the torturous hands of the Department of Homeland Security). It's one of those books that I find myself recommending to absolutely everyone I meet, but especially to middle- and high school students.
Fortunately, when not writing fantastic science fiction books, Cory Doctorow is also an advocate for Internet freedoms and basic Civil Rights (plus a fantastic writing mentor). His publisher, Tor Books (to whom I also contribute, via Tor.com), has agreed to send 200 free paperback copies of the novel to students at Booker T. Washington High School. And on top of that, you can download Little Brother for free in a variety of different formats directly from Cory's website, where he offers all of his books for download under Creative Commons licensing (the idea being that people will download the book for free, like I did, then tell someone about it, like I just did, which then leads to someone buying it. And it works). Even the National Coalition Against Censorship has gotten involved, writing a good ol' fashioned "strongly worded letter" to the educational administration in Pensacola.
So download Little Brother (it's free! You have literally no excuse!), give it to your friends and younger cousins and siblings. Because a society that still bans books is not a good place to live.