I agree with this one hundred percent. However, I would add that in my interpretation the users was likely talking about trending towards having narcissistic traits, and they weren't necessarily referring to NPD.

For a little context, my mother is the most narcissistic person I've ever met and she constantly told the people around her, "I like myself just the way I am I have nothing to change". She was emotionally and psychologically abusive and ruined every relationship she ever had, if there was ever a person that needed to change it was her. So anyone that thinks to themselves that they may be too narcissistic is way further ahead than a lot of people on the more extreme end of narcissistic personality traits.

I think other hallmarks of being narcissistic, which these are things she also did, accusing others of being narcissistic, creating and believing elaborate scenarios where other people are ruining your life or goals, consistently villainizing groups of people, the inability to maintain personal relationships, and most of all deflecting all responsibility for negative circumstances.

I think you could do any or all of this stuff and still not have NPD but a life long pattern of these things are a good indicator. I'm not a licensed psychologist or therapist just trying to share a bit of my experience.