It is definitely true that there are narcissists out there who call others narcissists. A famous one in our sphere is the YouTuber "TechLead", who referred to

It is definitely true that there are narcissists out there who call others narcissists. A famous one in our sphere is the YouTuber "TechLead", who referred to his wife as a narcissist while unwittingly revealing his own clear cut narcissism by describing many of his behaviours in that relationship (like having her have a GPS tracker on her phone, demanding she did certain things for him because he said she should, like investing his money when she had no interest in investment, and making out he did nothing but right in the relationship). Turns out his braggadocios personality in his videos wasn't much of an act -- he was merely exaggerating his natural thinking, which is why his "character" came so easy for him. In my own case, my mother was especially fond of hissing that everyone else was "selfish", while being herself a profoundly selfish and self-centered human being in every interaction she had with anyone (she was severely damaged due to a nasty childhood). This is because narcissists project, transferring all responsibility onto others, in order to keep the pain of feeling shame away from their fragile senses of self. This includes projecting the mental illness itself, which is where their tendency to gaslight comes from. But I think a narcissist using the very specific word "narcissist" to describe others is quite rare, because it's a bit too close to home. It has a very specific definition and presentation, and a narcissist is scared of anything that could affect their sense of self -- and an undiagnosed mental disorder is a particularly severe example of that, so it's dangerous for them. I'd say for the most part that subreddit is a force for good. Even if there's people in there who themselves refuse to accept responsibility, its reach gives those who are still in the dark a chance to discover the truth as to where they've come from.