why don't they just attach a rack to the wall with a sign that says "TAKE ONE"?
Because evil people, like me, will deface whatever they leave for the taking. I stop at a rest area while traveling that has a magazine rack free for the taking. It used to be stocked with the latest WT magazines and sometimes CD's. I'd carry my Sharpie when I would go in and write the web address for various web sites across the covers. One day the magazine rack had a sign on it that said something like "No Religious Literature Allowed" and that was the end of it. JW's weren't the only ones putting magazines in the rack. I remember "Guideposts" being in the rack. I didn't mess with those.