For the same reason you can but condoms in the supermarket, vodka at the ABC store, bullets at the WalMart (oops, scratch that one), K-Y Gel at the Food Lion, "Marilyn Manson" CD's at Target, and python-food (mouses) at the PetSmart.. . You are not supposed to use these products at the "point of purchase", LOL! Though life might be funner if you were, don'tcha think!