This focus on leadership in admissions is very well known, and manifests itself conspicuously in competitive high schools. There's a considerable amount of unspoken pressure to get "leadership" positions in school clubs, do "leadership" activities in community service, do varsity sports or other leadership in sports, and participate in ranked competitions. The list goes on and on. This breeds a lot of cynicism about people's motivations, especially as people try to game the system (with empty leadership positions). What starts to happen is that when people hear about a high schooler who goes off and founds a non-profit and does work in Africa (or something like that), people start to wonder whether that person did it just to improve their admissions chances. The sad part is that this person could very well be genuine.
EDIT (reply to below): Sometimes those people are college admissions officers. I'm in college now, so I don't worry much about that stuff anymore. I just recognize that the system is screwed up.