I disagree - as long as the students are asking 'why' from the biomechanical standpoint, I feel it is an important question. By the time they are advanced, however, they should know the biomechanics.
"Why" am I not surprised?
The complexity of "biomechanical why's" detract from learning the "how." The voluminous nature of the information, in conjunction with the complexity of the answers would preclude getting anything physically done. Most don't understand that because they themselves do not have the knowledge, so they see it as a "simple" answer to a "simple" question. It is not, nor has it ever been except for the proliferated and "dumbed down arts." Kinda like a child asking "why" the universe is so big. A simple answer won't give knowledge, only distract from it.
Where performance is paramount, you focus on achieving performance objectives first. In sports for example, coaches coach function. They don't stand around explaining every little thing, they want you to demonstrate performance. Experience will expose some of the why's, and will tell me when you're ready for a "why" or two.
The bulk of my students are extremely well educated, including several physicians. Even they don't ask me "why." They are looking for the "how" because they know as educated people the "why" will come as they gain experience.
Teachers who are always explaining "why's," and exploring myriad "what if" possibilities are intellectualizing a physical activity, and like most information novices within a physical discipline, they are enamored by the sound of their own voice, and it makes them appear "smart." Ed Parker called in "Hypothetical Kenpo."
If you really want to impress students, share with them "how," and watch them appreciate the effectiveness of their own ability now learned, and they won't care so much about "why." That's what happens in my lecture/seminars. They start out with "why" and when someone really actually for real teaches them something that they can see and feel works right now, they forget "why" and want to do it again because they know they are learning something.
This whole "why" thing is a western perspective, not found in the original teaching of the arts for a reason. No time - if your goal is to learn physically "how."
But, if you are teaching something non-physical, it's a different story, but I'm not. I believe in saving their butt from injury first, they'll understand why it saved their *** later, or study somewhere else. Isn't that right Bode?
I had a high ranking 2nd generation Parker Lineage Black Belt visit me recently. He said that he needed to have his why's answered or he could not learn. I told him that is what the commercial system has taught you, but it is not true, but I agreed anyway. We spent two hours together. I wanted to show him "how," and every time he would stop me and we would go into "Why." When we were through, he was flabbergasted with information that he never knew existed. When I got ready to leave I asked if he learned a lot. He said "well, yes, sorta." I asked him if he could apply anything I told him. He paused and said, "No, I'm having trouble processing just the why." My point exactly.
Teachers that don't have much to offer physically beyond perspiration warm-ups and calisthenics, talk a lot. I try to improve my students, and do what is in their best interest, even if they don't like it.
"This is Kenpo Self-Defense gentlemen, not math. Mistakes don't just give you the wrong answer, they hurt." - Dr. Ron Chapél
Take a lap.