You could argue that the person who makes a poor and violent choice is a product of two humans who may not have provided a good upbringing.
Sadly; not always true.
I will agree that the a child's background/neighborhood etc will influence future behavior a good deal, and generally kids from loserville neighborhoods are more likely to end up that way.
But I've known lots of kids from poor neighborhoods who are excellent citizens, and vice versa.
But across the board there has been a lowering of respect, dignity, pride etc - folks of all ages tell cops to go and get farked, teachers cop it as well, road rage is a growing past time, every second wall and building and bus shelter is tagged and/or graffitied....and so on.
It was unheard of when I was a nipper to hear on the news of stabbings and machete attacks at parties and in plain sight on public streets etc; now it's common place.
When I was a kid (yeah, yeah - "Back in my day" dribble - but it's true) if you told a teacher where to go, you'd cop a cane over the backside or palm of yer hand, then have to go and visit the Principal and possibly cop another one, and then get it from your parents when you got home.
Now; if the kid gets a detention for telling the teacher to go on a sexual holiday, there's a bloody senate enquiry and teacher gets a reprimand and worse - and still has to deal with the dopey parents who no doubt bleat "How dare you punish my Tyler"...and it's parents at all levels who do this.
God knows what would happen if the cane came out and the kid copped his right whack....