Hello; This story strikes a common chord. Know of such too many times. Saw the equivalent happen in the public school classrooms over a few decades. I taught from 1970 to 2004. By 2004 the discipline in the schools was near to nonexistent. I had worked out a pension so went home.But the guy who wound up with a knife in his gut was the subject of several long tear-jerking articles that detailed his sad upbringing, the terrible way that society had failed him and eventually drove him to make the poor choices he had made. We heard all about what a "good boy" he was, well-liked by neighbours and friends, dearly loved by family, smart, full of potential, the victim of a system that was stacked against him from birth, blah, blah, blah.
One of my co-workers knew this "poor lad" and his family. According to him...the guy was a dangerous antisocial POS and the world was a much better place with him deleted from it.
Spin doctors rule the world.
More to the point was the way the "trouble makers" became coddled and the well-behaved kids became ignored victims. Wish i could recall the exact wording the various principals and school bosses used when justifying the policies that became standard. But some of it matched your post about the upbringing and other blah, blah.
There were a number of things which happened but let me post one example. I had six classes each school day. In each class there were three to five troublemakers who disrupted pretty much every day. (edit -every day they attended) Their antics too often took up much of the class time. I suggested we put all the troublemakers into one class. That way in the other five classes we could actually work with the better behaved and maybe get something positive done. Each teacher would have to deal with the troublemakers for only one class period. A chore to be sure but better than each and every class all day long. My suggestion was not accepted of course.
I would ask students why they acted the way they did. Among the responses one stood out. That being the threat of their government checks being stopped if they kept skipping school. On another note, at a high school in NC I confronted a student in the hallway for ignoring the second tardy bell (yes second tardy bell. Also not like he was the only student ignoring the bells.) I thought he was going to challenge me but finally he moved on. Later a teacher warned me to leave him alone. Reason being he was out of jail after being charged with murder. The judge decided he needed to be in school. Same school where a senior football player threatened me after he got a failing grade because it might hurt his college ball scholarship. I gave him the failing grade anyway, but the principal called me in and informed me he was changing all the failing grades.
The last many years I see the culture of the public schools mirroring the general society. Not clear to me which drives the other.