…always remind me of the episode Storyteller (7x16) of Joss Whedon’s Buffy the Vampire Slayer.

Buffy: “Stop! Stop telling stories. Life isn’t a story. […] You always do this. You make everything into a story so no one’s responsible for anything because they’re just following a script.”

I guess talking about themselves in third person makes them feel less responsible for their actions. When they are judged from others, they don’t have to feel judged, they can join in judging without ever have to admit that they’ve done something wrong because from their perspective “he/she/it” did wrong and not “me”.

“They are dettached from themselves, from their own feelings and usually perceive the situation as if they had nothing to do with it, or do not want to have nothing to do with it.”

(Answer to the question “Why do some people refer to themselves in the third person?” on Experience Project)

Related: Illeism