On the other hand, why should I wash my hands if you can't give me a reason for cleanliness, neither theoretical (germ theory) nor empirical (it reduces disease incidence)?

At the time where the hand washing conflict happened there wasn't much of evidence-based medicine.

Today there is some evidence for checklists improving medical outcomes but they don't get easily adopted.

I think there's decent evidence that combining hypnosis and anesthetic drugs is an improvement over just using anesthetic drugs.

I think everyone agrees on this. Humans can't fully learn new behaviors just through abstract knowledge without practice.

I think the ability to be suprised by the right things is reasonably called knowledge and not only behavior.

There are dedicated software engineering majors, some of them are even good (or at least better at teaching to program than CS ones), but numerically they produce far fewer graduates.

According to Google some of their programmers are 10x as productive as the average. Can a decidated software engineering major teach the knowledge to be required to reach that level reliably? I don't think so. I don't think it even get's 2x.

Is there any software engineering major that tested whether they produce better programmers if they also teach typing? I don't think so.