Wrong analogy. It assumes that the human body have the same degree of complexity as, say, coffeescript. In no way. To properly (without killing the patient) and reliably open and then stitch the human body requires years of study and practice. While coding JS in vim requires, like 3 months, of which 10 weeks is studying vim :-)
I'm not speaking about why you're going to open the body (diagnosis) or what do you code, that's a different story.
Knuth's code has bugs. NASA's code had bugs. Programming as we conceive it is so close to impossible that it takes years of study and diligence to aspire to only being pretty bad at it. We're just reaching the quicksilver and bloodletting phase of our discipline's evolution, and someday our successors will look back and cringe just as doctors do.
Just the plain barrier to entry.