Not sure why people think Merkle trees are hard.
Discussion
They are hard to understand as much as atoms are hard to understand.
The existence of atoms is not hard to understand, but they are so versatile, it is difficult to map them to any one thing that we can put a finger on to say: "That... That is what atoms do."
When I first started writing Bitcoin documentation, I asked my mentor at the time (Mike Hearn) whether merkle trees were important to understand. 🤦♂️
Hash of hashes of hashes of hashes...
Nobody thinks Merkle trees are hard.
Wait... what? Why is the top one white? Why are the nodes fuzzy? How do you protect this structure from kittens?!