He literally says "most people" when he's talking about himself, cause he incorrectly assumes he's the smartest in the world. Therefore if he just learned something, then everyone else must not know that either.

He's like a toddler and doesn't understand theory of mind.

https://en.wikipedia.org/wiki/Theory_of_mind

Any time he says most people don’t know x it can be safely translated to I just learned x

Wait that a real quote?