There are ways to look at the requirement to buy health insurance.
In some states, you have a requirement to buy liability insurance in order to register a car. Why? So that the risk is spread to every car on the road, and there is some assurance that if somebody creams you with their car, insurance will cover it. In states that don't have this, companies offer uninsured motorist coverage, i.e. you are paying what the other guy refuses to pay in order to cover your own butt.
That's the idea behind requiring everyone to have health insurance. If your next door neighbor, the bullet-proof, I-am-young-so-I-do-not-need-insurance 19 year old, goes out and makes himself a paraplegic on his skateboard, he's covered by the policy he was required to purchase and the risk is spread. If he is NOT required to buy that policy, then he goes to the Emergency Room where he gets admitted for long-term care and rehab at taxpayer, i.e. YOUR, expense (of course, that's after the hospital bankrupts him by cleaning out the $42.39 he has in his checking account and assuming ownership of the small scraps that was once his skateboard.)
The law in this country requires the hospital to treat him, insured or not. If not insured, the taxpayer foots the bill.
If the law were otherwise, i.e. no insurance, no money, no treatment (it is that way in some countries), then mandatory insurance would not make financial sense. Ethical issues notwithstanding.
I am told (by a physician from one of these countries) that in some countries, if you are brought in for emergency surgery, the hospital and surgeon must know that they will be paid. If not, the surgeon simply walks away and you die on the table untreated. (My physician friend that I mentioned is NOT a surgeon, nor involved in emergency medicine.)