Requiring teens to participate in activities where they could potentially come out as losers will help boost their self-esteem. Adolescents, especially at the high school age, are a group of individuals vulnerable at the hands of their environment. While forcing kids into a competitive social environment may be uncomfortable for some, it will ultimately only show growth. If these adolescents are forced to be on a competitive team, both losing, winning, and just being on a team in general will provide them with social and life experiences that will lead them to thrive.
Competitive events among all ages, but especially among adolescent, have no real losers. Adolescents are strongly shaped by their environment, and even in the worst of loses they can learn valuable lessons that help them grow as a person. If you have ever participated in a competition and lost there are no doubt negative feelings that arise, but the reaction to those feelings is what becomes important to the mental state of an individual. Adolescents would ultimately benefit both socially and just overall in life skills if they were required to participate in competition with a team of any kind.