Same with understanding anything else in life - you don't really understand anything until you get to the point you can, in your head, predict a specific outcome, test it, and be proven correct, repeatedly.
(At some point you may learn to gain robust understanding purely from simulating things in your head, deriving insight from lower-level principles. But this itself is a skill, a hard one, which few people master. It's not something a random kid, or adult, can do.)
At a low level, you can point out all the patterns that are in multiplication tables, but they won’t be remembered until the student has internalized the facts.
At a higher level, teaching epsilon-delta proofs isn’t a good way to learn calculus. Memorizing the building blocks and the chain rule is.
Downplaying it to 'dumb ones' is not helpful when they can solve polynomials without much trouble but are getting burned on concepts that should have been drilled down properly in middle school.
They were saying that back in the day as well: https://en.wikipedia.org/wiki/Why_Johnny_Can%27t_Add
Memorizing solutions isn't useful anymore. We have google to list out formulas. A deep understanding of problem solving is far more important and something you cant trivially search.