That's because the profession requires that. Unless you are a medical researcher, doctors are supposed to use facts and prescribe meds/give advice/do surgery based on said facts. Like a lookup table for what to do.
Asking questions and understanding basic concepts is great for science or engineering when you have time for it. But if I walk in with a medical condition, you need to fix me using the best practice that researchers have proved. So please have it memorized, or look it up if you aren't in the ER or surgery room and have time for it.
However, your argument that building concepts increases memory longevity of said facts may have great value. Please become a researcher and prove it is possible to do this, while still accumulating the same amount of facts in medical school, or that current apps/internet resources supplement it in a meaningful way. Then perhaps will become standard practice in medical school, otherwise I don't see it changing.