2. Personally, I think the being more knowledgeable about (and conversant in) common psychological issues is great. Much better if we have a label for "depression" rather than just thinking "The world and everything is awful and I'm the only one who feels this way." Same for anxiety, attachment, all of that.
3. If young girls happen to co-opt it in a way you find self-absorbed, get over it, stop trying to police it and make a fake moral panic over it. It's no worse than astrology or whatever other loose avenue of self-exploration would be otherwise happening.
It to me sounds like the author fundamentally misunderstands the whole thing, this just is soaking in boomer energy. That is -- the premise that recognizing these trends is somehow shaming/bad and it's "better" if we all use loosely-defined unscientific terms like "nice-person" rather than looking at and challenging our overly intense and dysfunctional people-pleasing or whatever.
The way gen-z uses these terms, is that they aren't some hardcore disorder, but as a common parlance for real and addressable things to change about oneself (e.g. that talking on the phone can be uncomfortable, or making an appointment is stressful). Like gen-z may say "Oh I have insecure attachment" and they just mean "Sometimes I'm afraid to reach out for fear of rejection" and that's a healthy thing to talk about, even if the term they used is used a different way in the DSM.