The court is contradicting itself in reaching its decision.
1. The individual mandate is upheld as a tax, but not a compulsion of individual conduct in forcing people to buy insurance. But the court does note that the "tax penalty" is enforced when people don't buy insurance. In effect, the taxing power is being held to extend to congress taxing something that people don't do, rather than what they do. I don't think that's ever been done before.
2. The Medicaid extension is struck down as an interference in state power. It extended Medicaid to poor people who don't otherwise pay for insurance and health coverage. If a state doesn't extend Medicare, it can lose all the Fed contribution to Medicare. The court's reasoning is bizarre. If the Feds can make highway construction money contingent on state regulation of highway laws and state funding of highway construction/repair, why can't it also compel states to extend Medicaid to the poor?
The whole thing puts the Obamacare system up in the air. They can't pay for the state Medicaid extension, so poor people still won't get the medical coverage. The whole thing is very obtuse.
P.S. If the individual mandate is a tax, why does the Court have jurisdiction? The Anti-Injunction Act precludes lawsuits that would interfere with the collection of taxes, but the court first says that the individual mandate is not a tax, so the Anti-Injunction Act doesn't apply. Then it upholds the mandate as a tax.