Actually, I'd like to talk to them directly:
You are dumb. And a bad parent.
Here's why dumb:
Your kids can get those books even if you ban them at the school or the library. They can find excerpts online. They can go browse them at the bookstore. They can get a more clear-thinking parent to buy them for them and sneak them to them. So this whole little endeavor of yours is pointless. Go back to trying to ban violent video games if you'd like to do something fruitless in re: forcing someone else to "protect" your kid from something.
But what's more importantly, if you try to ban books you are severely lacking as a parent. This means that you, for some reason, don't have the temerity or respect to actually talk to your kid about what he or she reads. Even if you tell your kid you hope he or she doesn't read a book, and why, that's still preferable to leaving it in the hands of other people. Moreover, you would hope that you've raised children who, if they are intelligent and sophisticated enough to crave literature, can also handle the subject matter without having a nervous breakdown or turning into a pillar of salt or wetting their pants at an inopportune time. If you really did a good job raising them, they'll actually ask you questions about what they read and they get the chance to hear what you think and also use their own brains.
And don't you also just feel kind of bad? Kind of old and stuffy, when you try to ban books? Are you really willing to completely demolish your own inner child, your own sense of curiosity, by coming the big bad parent who not only wants to ruin things for your own kid but for others? You never were titillated as a child by learning about something a little outside your grasp and actually lived to tell the tale? Perhaps you're the kind of person who keeps balls that are mistakenly kicked onto your lawn.
Oh also: when you say "bad books" you sound like a scared little child yourself. Just sayin'.
But seriously, if you want to ban books, please ban mine too (it has curse words on it!) It would truly be an honor.