Why is This a Mystery and Not Common Sense?

Some goddesses are puzzled by this...like me...In 2010 the Smithsonian Channel did a Mystery Files special on Leonardo Da Vinci.  It received about 3 1/2 stars around the web when I looked it up, and had 2 on Netflix. I thought it was informative and well put together, though there was no real "mystery" to it. The narrator was making a big point of the fact that Leonardo most likely didn't "invent" any of the technological "innovations" and engineering "feats" found in his published notebooks after his death.

Well duh! These were private notebooks, like his artist's sketchbooks were he sketched and scribbled and generated ideas and kept journal entries. They were THOUGHTS. I keep various notebooks around with notes from other sources in them and ideas expounded in them and links and notes and generate ideas and add and subtract and I'm not even particularly a genius, or am I?

My point is, the narrators were making this big point about Leonardo as if he was defrauding history. LOL And the historians were very carefully saying that he was a genius man of his times who was a member of a select glitterati and had exposure to educated and talented minds and so had the opportunity to expand upon their thinking, that's all. This wouldn't be considered strange at all today; we would still consider him a learned and wise man with far ranging interests and a "Renaissance Man", to the narrators, it seemed a shock. It disappointed me a bit in the quality of writing from an institution of the caliber of the Smithsonian. I felt that they had dumbed down the presentation with narration for a fifth or sixth grade audience when it wasn't necessary. On the other hand, the quality of their renaissance experts were wonderful and the information that THEY imparted was well worth watching the show to see and hear. That alone was worth a solid 4 stars.
from a puzzled goddess mystifying on the history