Because at your age you are most likely to die of violence, not disease, and you'll get better care for violence without insurance.
Story here:
Researchers from the Stanford University of Medicine found that patients with insurance are less likely to get the best care than those who do not have insurance. They found that insured patients taken to non-trauma hospitals were 13 to 15 percent less likely to be transferred to trauma centers than uninsured ones. ...
Shootings and traffic accidents are the most common causes of death in this county among people under 44-years-old. Previous research has shown that severely injured patients are 2 percent less likely to die if treated at a top-ranked trauma center than at a non-trauma center.