I was just looking at another tutorial, and I'm realizing: it's a lot easier to explain how than it is to explain why. Which is why tutorials tend towards being a series of steps -- and the lesser of them contain no explanation for why these particular steps, and why in this way.
It is like the comment a lot of people seem to want to make when they look at my sound board. "How do you remember what all the buttons do?"
Knowing what the buttons do is the easy part. Knowing when and where to use them is a lot harder. Knowing why you would want to use that tool, though; that may be unteachable.
I think in most cases one ends up teaching a set of rules of thumb and usual-cases and best practices. And, yes, I apply these and use them every time I do sound. But what comes over time, over multiple applications of that rule and the rather more important application of ears to see what the tool is really doing is what, eventually, earns you the skill in knowing when not to use the rule.
The knowledge of, in short, the universe underlying those approximate, incomplete, and often inaccurate models. It is the difference, to take a concrete example, between knowing an SM57 pointed at a cab with the grill almost touching, pointing at the cone just outside of the dome, will usually work for reinforcing a guitar amp, and being able to hear the actual sound being made, to map it mentally in three dimensions and compare that to your mental map of the microphone's frequency response pattern, and chose a position that will suit the qualities you expect to need out of that instrument when it sits in the final mix.
Tutorials are, as the name indicates, one step even further back. Instead of teaching approximations that will let the student work and experiment and eventually (one hopes) learn, a tutorial teaches only a set of steps.
And we do learn that way. But it does become rather frustrating (and happens with more frequency the further you stray from exactly duplicating the example of that tutorial) not knowing why a certain tool was chosen. Why not a different tool? What are the pros and cons? What larger goal -- or what personal working method -- led the tutorial creator to chose this tool against another?
In re the last: this is just like following a reviewer of books or movies. The more you know the individual tastes and proclivities, the more useful their work becomes to you.