I guess I'm the only person that knows skinny people in real life, i.e. some of my class mates and coworkers, and unlike kpop stans I don't gossip about their physical or mental health, I don't accuse them of having mental illness or setting a bad example, and I don't insult them with words like "gross" or "skeleton".
Since I wouldn't treat people this way in real life, I don't treat idols this way online either, you wanna know why?
1. Unless I'm close with someone I have no way of knowing the status of their mental or physical health.
2. It comes off like insecurity or projection to assume every thin person has some illness.
3. Even if someone does have an eating disorder, it's not my place to talk about it, as my insensitive comments could make their disorder worse, and considering I'm not a doctor (and I'm sure 99% of these kpop stans aren't) it's really not my place to give my two cents.
4. Nobody deserves insults and to be singled out for their body, especially if they're sick and dealing with negative body image.