Cognitive load is what matters

Children were always told to cram as much as possible into their memory. It was even claimed that, more you put into memory, you mind works better.

Not quite. Human mind has evolved to interpret the sensory data collected by senses, and cause necessary action. Some of that interpretation uses memory to correlate the perceived data with the memory data. That's pretty much it.

Overloading the human memory with tons of data which is not related to the context in which the person lives, can cause negative effects. I suspect it can also cause faster aging. New experiences, new information is like scales on a tree trunk. As you accumulate more of it, you age more.

I love learning and until recently despised teaching. I felt like a double agent nodding along at all the lies my teachers told me while I mastered the material almost in spite of the teaching instead of because of it. This became a real problem I college when the material was no longer a given. There were going to be people who flunked because the material was just too hard.

I have always been a C+ student of rote memorization at best. Almost enough to be good at trivia, but not enough to do well in coursework. I am always trying to build a Theory of a System from practically word one, which is the fifth stage of learning, where rote is the first.