“Narcissistic behaviour” is an ableist dogwhistle. We don’t talk about enabling deaf behaviour, or autistic behaviour, because those are disabilities we treat with a modicum more respect.

Infantilising mental disabilities is a dick move.

If you’re not a psychiatrist, then you don’t have the training needed to diagnose someone with a mental disability. I don’t care whether your parents actually have NPD or not, but the risk of armchair diagnosing someone is that you’ll just amplify stereotypes. You diagnose them because they meet a stereotype, and then you study their behaviour and reach the conclusion that narcisstists act like the stereotype, and then you spread your conclusion. It’s citogenesis.

Also “narc” when used to say someone has NPD is straight up a slur.

No, I have NPD and we’re called narcs sometimes. It’s often used in the community as a shorthand, but generally if it comes from a neurotypical it’s a slur. I’m aware of the other meaning of the word and I don’t have a problem with it, but I tend not to use it because it just reminds me of the homonym which is actually offensive.