1. I'm quite sure the format of my post made it clear it was part of an interview, making it, for all intents and purposes, a quote.
2. I don't think the backstory is a direct account of the Sages. The manual of ALttp makes it clear the backstory is an amalgam of various legends and sources, including Hylian texts, the Book of Mudora, and oral tradition. The same manual (a source I'm sure you'll have an issue with) states "Their descendants settled in various parts of the world and passed on their knowledge and magical lore to all people. But in its passing, the lore was often distorted or lost altogether." <--there's some quotations for ya.
3. a source probably more to your liking, the actual SNES intro, states "Long ago, in the beautiful kingdom of Hyrule surrounded by mountains and forests... legends told of an omnipotent and omniscient Golden Power that resided in a hidden land. Many people aggressively sought to enter the hidden Golden Land... But no one ever returned.
One day evil power began to flow from the Golden Land... So the King commanded seven wise men to seal the gate to the Land of the Golden Power.
That seal should have remained for all time...
...But, when these events were obscured by the mists of time and became legend..."
(I think that last part is pertinent)
So no, I don't think Hylians are idiots, but I do think that depending on exactly how much time passes between Oot and ALttP, a LOT of info could have been lost. Again, my own personal opinion which is neither more or less valid that anyone else's.
For whatever reason, you are very obstinate and dismissive of other people's opinions. It is okay for people to have different rationalizations for the various inconsistencies. The actual reason for inconsistencies is the natural outcome of making a series over a 25 year span, with different teams and retconning certain events for the good of the current game. Ultimately, however, the retcons are Nintendo's to make.