You have to either be on the mailing list or purchase the catalogue at the store. There's no conspiracy to slip the catalogue to kids without their parents knowing. A&F has no social agenda other than making a ton of money.
I agree about the money part, but by allowing under age teenagers to purchase in the store circumvents parental control over what their children see. It's a matter of rights of parents that is violated here. You have to be at least 18 in most places to buy skin magazines.
What reputable merchant sells what could be considered porn to children? Here is a good take on it from the SanFrancisco Journal:
http://www.dadsanddaughters.org/action/SF_Chronicle.pdf