Focusing on this in particular and not directed totally at you but also the guy who said all books "teaching people to do illegal activites" should be banned.
Now what happens if these books are banned. Good no more evil instruction books for illegal activies. Now down the road the government starts to overstep its rights and begin to oppress the citizens. Suddenly we find the gov't doesnt care at all about the bill of rights anymore they will do as they want when they want. So suddenly the protection provided by the bill of rights is null.
The point I am trying to get at is that though we may disagree with books like this, but to just let the government censor them is just as wrong as the content of the books. We as citizens have a duty to watch the government and tell them when they are out of line. I may disagree with this book or books teaching how the grow marajuana or other drugs, I will tell you now that I would be one of the first to be fired up about the banning of these style books. I see it as citizens just handing over their rights into the hands of the government as they are "better suited to protect us as citizens". Let these books be circulated, It is your duty as a parent to watch for the signs your child is being molested or taken advantage of sexually.
Maybe I have just read 1984 and Brave New World a few too many times. I hope my point is relatively clear with this post as I know my thoughts are very congested and can be difficult to follow.
tl;dr = Slippery Slope