Are you asking why teens must pay the adult price? I'm a little confused on the question. If it's about price, it's just the way to make money. Some business's start charging the adult fee at a certain height (which my son reached at age 6, so that was frustrating). If this is your question, it's not that they consider a teenager an adult... it's just that they only give a discount (child's price) for a small group of people. In restaurants, it's often the young children who have small appetites and eat very little. In amusement parks, it's because young children usually only ride the kiddie rides, and therefore it's not fair for them to pay the price to ride all of the rides (when they can't).
