Well, I disagree with you.

Especially your training pilots example. *Also* knowing the why of aeronautics is FAR better than "Do this cuz I said so." That approach will get a pilot killed when things don't go as planned. Understanding the why of how planes fly will help the pilot improvise in emergencies. Yours is the argument from authority "Do this cuz I said so." That's a playbook to work out of. Yours tells ppl WHAT to think. And that's necesary. But mine is the argument from science, logic and technology. Lift, air density, up/down drafts, air pockets, prevailing winds, etc etc "Here's WHY planes fly, now think for your yourself when the fit hits the shan, and the playbook didn't work."
Same with guns. Knowing the "why" helps the individual figger out if the recommended action will work for his unique set of variables.
Meh. To each his own. I'm always gonna wanna know the why. I don't feel badly if you disgaree.