Stans (who take their name from Eminem’s song “Stan”, where it wasn’t a positive association) get quite intense, to the point of breaking and entering private property, stalking and causing road accidents, writing messages in their blood, even poisoning them, and that’s just the “selected incidents” on Wikipedia. https://en.m.wikipedia.org/wiki/Sasaeng_fan
Every fandom of any type of a certain size has insane fans (looking at you sports teams and fans).
I understand your point but there’s more interesting analysis here than “this is the same it’s been done before.”
My completely anecdotal experience seems to contradict this, the most "mainstream" example I have was when I saw Loona's AMA on the front page of reddit. I read through the thread, and you're going to have a hard time convincing me the average poster was not a 14-year-old girl.
I've also listened to some kpop myself and more directly I always thought, yes, this is type of music I'd go for if I had severe ADHD (not an insult to the genre, I can't say it was "bad", it just gave me that impression)
The behaviours of the K-pop fans in my life don’t resemble anything like the fans of boy bands growing up. Do you remember vast swathes of wealthy, intelligent 30-40yr olds listening to Backstreet Boys, selling and trading merch, building shrines, etc