You just don’t get it.

ship owners buy medical insurance for their seamen.

Don’t want to buy insurance? Don’t own a ship.

Car insurance is required (mandated), but not if you don’t own a car.

The health insurance mandates are required for everyone by virtue of a heartbeat.
Now you might think that is ok. And maybe it is. The Supremes will decide.

In the meanwhile that example is not relevant.