This is not, in fact, Jefferson warning against nationalized health care, as the quote has been modified to imply. It is taken from a note on the State of Virginia, warning against government intervention in religion. Against legislating morality or other ideas brought from religion. Even that religion he claims as “true”.
What’s interesting is that he believes government interference will allow any current corruption to be maintained. Under the corrupt religious beliefs, upheld by the state, people’s very souls were in jeopardy. He is arguing vehemently against such interference. And the comparison he chooses to make is that of the government controlling food and medicine.
Our souls are at risk, just as our bodies would be if the government were to take control of our food and medicine. He’s using food and medicine as the obvious example. As the “duh, that wouldn’t be good” comparison. Today, Jefferson might have said, “We need the government to legislate morality like we need a hole in the head”. “Hole in the head” is the “duh, that wouldn’t be good”. We don’t need that.
Jefferson’s “hole in the head” has taken very little time to become society’s plea. And it is as good for our bodies as legislating morality has been for our souls.