> Why do we expect school or university to teach „understanding”.

Having been taught in different systems that emphasize understanding vs memorization, I'd have to disagree. The teachers and the overall academic system can encourage, test for, and reward rote memorization. Or it can encourage, test for, and reward problem-solving, critical thinking, and understanding.

Everything from the way teachers lecture, to assigned reading, to assignments, to tests will influence how students think and what they optimize for. There will always be exceptions who forge their own path, but most students like most people just go with the flow.