1. People who are really good at things are not necessarily the best teachers of things.
2. Some people who are very good at things have a difficult time understanding what's actually happening mechanically when they do those things.
3. Sometimes what you would teach a beginner, intermediate, or even advanced person to do...is not the same thing you do as an elite.
As an example...a LOT of professional basketball players have wonky-looking shots...but those shots work for them...and many are working on them consistently. I would expect that if they were teaching a clinic, they'd teach people to shoot with what is generally accepted to be "good form" (elbow tucked in, hand directly behind the ball, etc). Some of them, if they had never had a video of themselves, would probably even think they had good form because of the way it feels...even though they definitely do not. I've been to a lot of basketball clinics in my day, I've never seen someone say "you know what, throw your elbow way out like a chicken wing when you shoot"...even from people who throw their elbow out like a chicken wing when they shoot.