They said that if Congress is going to enforce and fund it, they can only do it as a tax.
Think about the practicalities of that.
It’s very likely Congress will try to integrate this with income tax and withholding and your health insurance provider will be required to file information with the IRS about your insurance status and changes in it. Oh, what an amazing and even more unpopular mess this is going to be.
Congress left a flaming bag of shit on the Supremes’ doorstep, and John Roberts just walked it back across the street, still on fire, rang the doorbell and ran.