Indian math system is not memorisation based either.

Math anywhere in the world is all about how many patterns you know/seen. And inventing new math is all about changing one small thing about the stuff you already know and see if it remains logically consistent.

Knowing what to change largely depends on the stuff you already know. To that end even if you don't memorize facts, you still need to memorize patterns.

You have to memorize something. Nobody invents the Apple pie from scratch.

You don't "memorize" when learning math. You solve problems and then you happen to learn to recognize patterns and start to remember some things. Those are not the same learning activities.

Memorization is something else. I have seen students trying to memorize math and these were all bad students. Completely lost when the exercise changed slightly.

If we start to use "memorization" for "any time something is remembered" then the word will loose its meaning.

"Drilling" is perhaps the better word. The point is it benefits from repetitive practice.