Humans are animals. Like other animals, we have an innate sense of fairness that works on very primitive terms. If we see ourselves doing the same work as another, but getting less reward, that's unfair. It's like the experiments done with chimps... push a button get some food. If chimp A gets 1oz of food per button press, and chimp B gets 2oz of food for the same button press, when chimp A realizes the difference you are faced with one ticked off chimp. They will even stop pressing the button altogether even though it would be arguably better to get something than nothing. They are programmed, to use your terminology, and that programming is part of our evolutionary history.
If everyone pays into health insurance, but one guy gets nothing while another guy gets a $100,000 pay-out in the form of a surgery, that absolutely hits humans in the monkey back-brain. It is unfair at an evolutionary level. It's exactly the same as when chimp A realizes that chimp B gets twice as much per button press.
You hear that if you talk to people. I've talked to people after receiving major medical care. How do most describe it? By how much it hurt? By the recovery time? By how much better life is afterward? No. The most consistent description is in terms of how much it cost insurance. It was a $40,000 procedure, a $125,000 procedure. Why? Because after paying thousands of dollars into health insurance, that's the payout...and it was a jackpot! It's proof that you weren't the sucker that is getting only an ounce of food when someone else is getting two.
People don't think that way... they are driven to be that way by a billion years of evolution. Fairness means getting back what you put in, and the more you pay in (health insurance premiums, taxes, et cetera) the more you are driven to get out if you want to feel like the system is fair.
I think it's another variation on the Tragedy of the Commons..... by creating universal health care (whether through regulation of business or direct government provision) you create a Commons, and the natural response to a Commons is that everyone wants to extract all they can from it because someone else benefiting when you don't is unfair in that back-brain evolutionary sense. You are then forced to exert more and more control to try and keep people from abusing the Commons, which ties us back to Pilot-induced Oscillations and totalitarian governments and a whole host of other problem. The reality is that human nature rarely allows us to take the most direct approach to solving problems, and creating a health-care Commons is a very direct approach to paying for health care.