Because the category got placed under performing arts instead. It could probably fall under either place, but the important thing is that the category exists. If you want to visit it, you can search for it on the Browse Categories page, or go to it directly here: answers.com/Q/FAQ/9973. A reason to place it under Performing Arts instead of Sports might be because band members have to know how to play their instruments and the music before they can march and sometimes Marching Bands will perform sans marching.