I'm required by state law to carry auto insurance, and many kinds of businesses are required to carry insurance or post bond- the Federal govt requiring me to carry medical insurance is no different.
+1 to what both cybrsage and Hayabusa Rider said about this.
I only have to add that you brought up a state law, much, much different than a federal law especially since the state has this power but the fed does not. Again, powers not specifically enumerated in the Constitution to the fed are reserved for the states.
Also, you are only required to have car insurance because you own and drive a vehicle. You are not required to own and drive that vehicle are you? You can argue that it is a necessity but no one is forcing you into having that vehicle, there are alternatives. Also, the business insurance and bonds that you speak of are required because those entities choose to conduct business in a particular state. Just like the car insurance, they are not required to conduct that business, it is by choice that they do.
The health insurance issue is a vastly different thing. The people who are for it are saying that you are required to have health insurance just by being alive. You don't have a choice in this matter, unless you are advocating mass suicide as a way out. You do not have to engage in anything in order to be required to have it, just exist. The government is trying to penalize those who choose to do nothing, and doing nothing is their God given right in this case. Now if states required car insurance even if you don't own and drive a car, then you might have a case. This is exactly what advocates for the health insurance issue are saying. They are requiring you have insurance even if you, the person who has the right to chose, don't have anything you deem worthy of insurance. If you are healthy or just plain don't want to pay for it, that is your right.