Maybe they get accustomed to being criticized or insulted by users they consider their approximate equals or superiors, and if they are insulted by an apparently inexperienced, unrelated or unpopular user, they wonder why the outsider is getting into the issue. They think of themselves as being higher than the criticisms of apparent novices, and focus on that confusion, using it as an equally asinine defense.
This is only a bad justification for the way I might have used it, I don't agree with the idea.