Assisting the needy in health care is a "moral imperative" -- not a constitutional right. The two are as different as a squirt gun and an Uzi.
If something is not permitted under our Constitution, the federal government simply cannot do it. Period. The Founding Fathers vigorously debated the role of the federal government and defined it in Article I, Section 8 -- spelling out the specific duties and obligations of the federal government. Most notably, this included providing a military for national security, coining money, establishing rules for immigration and citizenship, establishing rules for bankruptcy, setting up a postal system, establishing trademark and copyright rules, and setting up a legal system to resolves disputes, in addition to a handful of other matters.
Charity is not there.
Congress began ignoring its lack of authority for charity before the ink dried on the Constitution. When Congress appropriated $15,000 to assist French refugees in 1792, James Madison -- a Founding Father and principal author of the Constitution -- wrote, "I cannot undertake to lay my finger on that article of the Constitution, which granted a right to Congress of expending, on objects of benevolence, the money of their constituents."
But what about the Constitution's general welfare clause?
Madison said: "With respect to the words general welfare, I have always regarded them as qualified by the detail of powers (enumerated in the Constitution) connected with them. To take them in a literal and unlimited sense would be a metamorphosis of the Constitution into a character which there is a host of proofs was not contemplated by its creators."
And consider government welfare's effect on people's willingness to give. During the Great Depression -- before the social programs that today we accept as givens (Social Security, Medicare, Medicaid) -- charitable giving increased dramatically. After FDR began signing social programs into law, charitable giving continued, but not at the same rate. People felt that they had given at the office and/or that government was "handling it."