What do you think insurance is? Everyone pays, only some people actually use it. If you get hit by a bus the day after you get insurance and need $2 million in surgery and therapy, the insurance company pays for that. And now, thanks to Obamacare, they can't just drop you.
And others have addressed the part about risking your own life. In theory, yes, that's fine, except hospitals are legally required to treat everyone regardless of insurance. So the rest of us are paying for it one way or another. This just forces the freeloaders to pay up.
Oh yeah, and it also keeps people from being dumb about not paying for insurance when most of the time it's a good idea, financially.