I've been, worked with, and now get harassed by the rabid children of the burbs. Some of your school friends have things I'd rather not mention and we all know it too, even your parents.
In the opinion of some guy on the internet, I would propose my own view that I would rather you stunt your growth and get a concussion in football and weights than lay in the streets after I kick you out for laying around the house. Someone out there; their life was traded for height. They are a very tall crackhead now. The best of us show up at walmart at 25 looking like Gummbie. A little exercise, intent and purpose at a young age is what saves this world. The answer to "whats his problem" in almost any circumstance is this, short healthy happy-ish adults who have never been given a chance and we wonder why they don't do anything.