I agree with the author on this point. It has happened with me. Whenever I have pointed out the errors committed by the fellow members, I have been branded as acting as an editor myself.
What actually happens is when you are used to a site, you tend to get the crux of the site and the way you need to behave in the site. When you see a member moving away from the guidelines, you feel like pointing out the same to the member. And when you do so, the concerned member retorts saying it is his prerogative. It should be understood that the site works on the basis of certain guidelines and one has to abide by them. There is an irony here - the same member who makes those comments that it is prerogative fails to understand that it should be the same with other members as well. They make it a point to poke their nose into what others have posted saying it is not allowed.
Double standards, I must say!
Live....and Let Live...!