There is no opting out of this, I either buy insurance, pay the fine, or stop breathing. The government has no right to do this.
The supreme court said it could.
As to remaining there or not, that is where it should remain and having the government further intrude does not help that. If I opt to not purchase health insurance and get cancer, how is my tiny little fine actually making up for the hundreds of thousands of dollars worth of bills I am racking up? It doesn't, and it still ends up between me and the hospital.
You're still not thinking widely enough. It's not just your fine, it's the fines for the ~10k others who didn't get cancer. You know, the way insurance works.
It's also not supposed to compensate the hospital so much as miscellaneous government costs, like the chances you'll end up on medicare after you've lost your job due to your untreated cancer(because you didn't have the insurance or the credit rating for the hospital to treat you), etc...
As you say, it's insufficient for this purpose, but it's what they could get away with. The real idea with it is to make NOT getting insurance a little more expensive, making getting insurance look like a better deal so more people actually buy it.