There might be a reason, but it's probably not a good one. These things are chaos-theory-like[1], with the causes so tiny that they're impossible to observe or predict and so may as well be random. It could be as simple as "One day, someone was in a bad mood and took it out on the nearest person unlikely to fight back. They realised that they enjoyed it, and did it again. Others observed and joined in." - by the time it reaches that point, you're already talking about group bullying by multiple people. Knowing the cause, or that there even was a cause, doesn't really help anyone.
> But I seriously cannot believe this if there is not a single reason WHY they did such horrible things.
ugh. just fucking ugh.
OK. I got the crap bullied out of me in school. You know why? Because I was nice. and because I was different.
When I was around 14 I had to move schools because I was too terrified to go in. I was a boy, but I liked having long hair, so of course that was a huge vector for bullying, amongst other things. One time I even got chased around a classroom by someone trying to cut my hair off with scissors.
Don't ever fucking try to fucking justify or contextualise bullying in a way that blames the victim.
That link of yours is amazing. A lot of thought put to the problem of high school hierarchies in the US. I disagree about it not being about the age, though. School goes slower where I live so the 12-16 year period hits in secondary (youth) school instead of high school. The bullying basically stops as people go to high school. The pupils are still in the classroom. The situation doesn't change. Yet the bullying stops.
I think it's partly because grades and school simply don't matter prior to high school (in the US, at least). Theoretically, as long as you don't fail, you could barely scrape by in elementary and middle school and it would never make a difference in your life. School then is something you put up with, you "put your hours in" every day, but your performance doesn't really mean anything to anyone, so kids have all of this pent-up energy during school hours and nothing worthwhile to put it into. Into social hierarchy bullshit and bullying it goes. There were definitely instances of bullying/power hierarchies in my middle school, but for the most part kids were just indiscriminately dickheads to each other because we had nothing better to do in our boring little world.
Once you get to high school, your grades actually matter for deciding the course of your life, so all of a sudden you have to try in school if you want to get into a good college. Three consequences: kids have less energy to waste during school hours, they actually have a goal (however meaningless) to work towards, and being a good student becomes cool (as long as you meet some baseline level of attractiveness and social skills) because (in an ideal world) it means you have a brighter future ahead of you than flipping burgers at McDonald's. At this point, most kids just want to focus on their "work" and enjoy their remaining time with friends, not trying to inch their way up a pecking order. The exceptions were the kids that knew they had special privileges (football players and cheerleaders with rich daddies), and the poor kids with the worst grades that knew their futures were bleak.
It pains me to say it, as a slacker that hated the "school" part of school much more than the social interaction, but maybe making grades "matter" earlier on would improve the quality of social interaction in middle school. I don't think that's worth wasting more years of the lives of children, though.
Two other non-age related factors: American middle schools encourage microcosms to form by generally being smaller than high schools, and by having tighter-knit class units (at least in my school, you stuck with the same kids for everything except electives). Among the first things I thought when I started high school was "there is no way I could ever meet all of these people," later followed by the realization that no one else gave a shit about strangers anymore either.
I remember doubling 10th grade. As I entered the new community of new grade 10 students, I noticed that one girl was being bullied. I did not understand why. I asked the other students about it, but they were never able to explain it to me. Some didn't understand either, but had accepted the situation as normal. Others, all from the same village as this girl, seemed to participate more actively. Somehow, sometime during their elementary school years, the culture formed by the students of that year in that village had to come to include bullying that girl. There might have been an origin to it all, but when I entered their subculture in 10th grade all that was left of that narrative was an unexplainable shared dislike of that one girl.
Bullying is mainly a way of gaining status and popularity for youth. They gain advantages for themselves by abusing those weaker than them. Think a bit about how offensive your question is, though. I am quite disgusted when people ask it from victims of bullying, it's not beneficial and shows a lack of empathy and understanding.
Imagine asking this about the Holocaust.
"I seriously cannot believe this if there is not a single reason WHY they did such horrible things"
Imagine asking this about slavery.
"I seriously cannot believe this if there is not a single reason WHY they did such horrible things"
Imagine asking that from a little girl who is tortured psychologically every day for years.
> not a single reason WHY they did such horrible things
There are reasons, but to a warped mind, cutting someone in a line is enough for death by hanging. I mean Ted Bundy probably had some reason for doing the things he did - maybe a girl dumped him so he decided to take revenge (on other girls).
It could have been nothing else than just wanting to rise up the ranks and enjoying the abuse way too much.
