People aren't insured because they don't care about being healthy. They are largely uninsured because they can't afford health care and their rent or might not even have jobs at all. The large number of people who have nowhere to turn to and are risking their health should be helped out by the government.
I beliebe that large numbers of uninsured inddividuals does give cause to universal health care. Health care, especially in the United States, is incredibly expensive and people shouldn't be forced to choose between being extremely unhealthy (or even die) or spending their entire life savings to get a simple procedure done. Health care reform is tricky and I don't necessarily agree with how it's currently being taken care of, but I do think some sort of universal health care is necessary for this day and age.