Sham, you are wrong, my friend. There are many ways to do things effectively. You are the ONLY person who insists on there only being one "right" way on this. Even the video that you posted shows wrist movement, so he must be "wrong" too by your standards. Yet, you obstinately state that it's "right" when you said there there must be no wrist movement before, and this video clearly shows movement in the wrist.

There's absolutely nothing wrong with that stropping in Bart's video, and none of us have any expertise on this matter to the point to be so assertive. This is a time where you couldn't be more wrong.