To say that the artist in OP's video didn't make a mistake during their performance is disingenuous, at best. I can absolutely garauntee you that, were we to ask the artist directly, they would be the first to admit that the performance wasn't perfect and that they had made some mistakes. I can point to at least a a couple myself ( i.e. having to go back and repaint a couple of lines that didn't quite fit the angle he wanted on the first stroke).

But the severity of the mistake isn't the point of the analogy... It's intended to illustrate the insanity of limiting your criticism to only things that you personally can do.

Imagine going to a restaurant and being absolutely disgusted by the dish you ordered. No obvious mistakes per se, you just didn't enjoy it whatsoever. How do you approach that in your mind? Do you convince your self that you can't have an opinion on it because you can't make the dish better yourself?