I think that, if there were a simply defined reason for all this, the powers that be would have dealt with it by now. I think it's a very complicated issue which can't be resolved by changing one or two things. It's a cultural thing which has built up over a long period of time and consequently doesn't seem to have a simple root that you can treat.
There is so much more violence around than when I was growing up, not just on television, but in games, films, etc. Also our consideration for each other is less than it used to be. Language is more aggressive, driving is more aggressive, people seem to be obsessed with their own rights to the exclusion of the rights of others.
Children misbehave in school and their parents go in and attack the teachers who report it. What sort of message is that sending? Referring back to bullying in general, the sooner they start treating these attacks as gbh etc, the better. A lot of physical attacks in schools don't even have the police involved because the schools feel it is an internal issue which they can deal with. This is wrong. Children who attack others physically need to learn that it is assault, not bullying, and will be dealt with as it would be with an adult. Being on school premises doesn't make it a lesser crime, but it is treated as such.
A friend's son had his nose broken by another child in school and at no time were the police involved. The school insisted they could deal with it and the parents went along with that. I don't think I would have.