I suck at memorizing and dont use it as a study technique, but when picking up a new skill I cant say "what are the underlying principles?" because I lack the context.
(Well I can say that, and then I'll get frustrated when no one can express them for me, and the ones that try dont make sense)
I suspect that the memorization is just brute force via flashcards or practice and that's more straightforward for people to 'study'. The other method of deriving and actually understanding is generally harder and usually relies on existing knowledge you learned in previous grades (it gets harder to use that method over time if you haven't been). It's also something the teacher may not be capable of either depending on school district.
I'd guess for a large percentage of people they never learn the non-memorization form of studying because they're never really exposed to it and because it's often not rewarded (sometimes it's punished). The brighter kids might pick it up anyway, but I'd suspect they could do the brute force memorization like the other kids if they similarly weren't as capable of it.
It's fallacious to think that one type of action can be harder than another type of action, when within each class of actions there is a wide variation in difficulty. Thinking from first principles is not harder than memorization when the first principle is Newton's first law and the memorization is every chemical component of cellular metabolism. Another example of the fallacy would be thinking that the humanities are innately easier than physics: sure, a two-page essay is easier to write than a two-page solution, but you can go in and crank up the number of pages per day a humanities professor is expected to write until it is as hard as you want (it turns out that to some extent this has already happened, you would be surprised if you found out exactly how much output they are expected to have).
In physics, the memorization is easy and the first principles are hard. In biology, the memorization is hard but the first principles are few. That's the origin of why people with biased strengths are better suited to one or the other.
There are also some things that are harder or easier for people because we have innate hardware for certain things. Recognizing facial expressions (or really interpreting any sort of visual input) compared to doing complex math in your head. The Type 1 vs. Type 2 systems from thinking fast and slow - some things are generally easier for humans compared to other things.
The point of all this being, you have to recognize where you stand on the reasoning-recalling spectrum and adjust your learning strategy accordingly. Something that works for someone on one end might not work at all for someone on the other.