Bare in mind most of the kids in question were born here, not in their parent/grandparent's countries.
You're right about all this, but what I'm saying is that in the long term, teaching people the truth and to act right will not end this. Breh A from Brixton isn't gonna let Breh B from Peckham slide for rushing his brother last night just because we're suppose to love eachother. No matter how many times you tell people to proceed maturely to a problem/situation, as long as those problems keep occurring, there will always be the opportunity for them to react dangerously. People naturally adapt to the environment they're in and you'll find that even kids from stable homes in the middle of a council estate will end up carrying weapons if they know people around them are doing so.