bad analogy..
yes.. You can speed and get a ticket.
You can also chose not to drive and thus not get a ticket. Nor be forced to by insurance for a car you do not own.
You can not live with out being affected by this tax/fee/fine/penalty.
The point is that IT IS A COMMAND.
Pick your own analogy.
There are thousands of laws where a government says "you must do x" and if you don't there is a penalty of a monetary fine or jail time.
ObamaCare says "you must do x":
"An applicable individual shall for each month beginning after 2013 ensure that the individual, and any dependent of the individual who is an applicable individual, is covered under minimum essential coverage for such month."
...and then says if you don't, there is a penalty:
"If an applicable individual fails to meet the requirement of subsection (a) for 1 or more months during any calendar year beginning after 2013, then, except as provided in subsection (d), there is hereby imposed a penalty with respect to the individual in the amount determined under subsection (c).
Roberts is wrong on this, and Scalia, Thomas, Kennedy and Alito were right.