Much of what you say is correct. Once you decide to provide government healthcare, you have gone down a very slipery (and foolish) slope.
Regarding the supposed unconstitutionality of this action, it clearly is not. Unfortunately, the courts, (which decide these matters) have said it is legal. Rather than trying to interpret the constitution for ourselves, we need to elect legislators and officials, and get appointed judges who will move to ammend the COnstitution to outlaw such actions.
There's no way that this nonsense is "clearly" constitutional. Just because the Supremes say it's in keeping with the Constitution doesn't make it so. Remember that it was a Supreme Court decision which "discovered" that a person's right to privacy somehow makes that person exempt from prosecution for murder for aborting her unborn child.