“How could the individual mandate NOT be a tax when the compliance is reported on each person’s Federal tax return, and the penalty is administered as a tax liability that is tracked and enforced by the IRS?”
Because the individual mandate was unconstitutional; it was a PENALTY, not a TAX. It is unconstitutional to TAX someone for NOT doing something. A person can be legally PENALIZED (such as pay a fine), but that penalty is not a tax (even though payment of which goes into the government or general coffers).
The 5-member majority in Sebelius (2012) did not want to have to rule on the constitutionality of ACA sans the individual mandate (severability), for fear the whole Act might fail. Thus, in 2018 the penalty was reduced to zero, pretty much making the whole issue moot.
Where does it say that in the Constitution — especially when you consider that the ACA “penalty” was imposed as part of the Federal income tax?
Sorry — in my previous post I meant where does it say THIS in the Constitution?