There are no reasons

I had not planned on chiming in, but I'm a mom and that's pretty much who I am for the most part, especially when it comes to opinions on life, death, and loss.
You bring kids into the world, some of us too young when starting that process. Not as much of a youngster as some, but in my case, immature enough to have little clue of what I was getting myself into.
What I do know, is that every day of Junior High School was hellish and full of relentless abuse. Did I want to kill my tormentors, no. Did I want them to disappear off of the face of the earth, absolutely.
What I have never been able to understand, and it may seem naive, but, why does the behavior become the norm? The answer I was always given was, "it's human nature." What the fuck does that mean? With that, comes the answer; So is the response, and if it is killing other kids, then do we accept that as natural as well?