But now you can, so we're on to the next whack-a-mole.

But it's not a hard concept, it's just unfamiliar to them.

People being confused by a concept after it has been taught to them suggests that either the concept is hard or the educational process inadequate. Confusion on initial introduction has nothing to do with difficulty.

are hard concepts from math and science bad concepts? should we discard calculus?

is potty training a toddler a bad concept? they initially struggle with it and some find it hard

is a healthy diet a bad concept? people without prior knowledge of what's healthy and what isn't are likely to struggle