So to play doubles avocado on some of this shit, I have three kids and really don't want them to be on social media or for there to be any smartphones in their schools. That stuff is undeniably toxic and has fucked up the current generation of youngsters completely.
As for good behaviour zones, I live near to a homeless hostel and used to have a lot of problems with tramps hanging about drinking and having arguments outside my bedroom in the middle of the night. The council put up some 'no alcohol' signs, and it just meant that we could get the police to come and move the tramps along quickly, it got rid of the low-level nuisance and now the street is quiet at night.
On the race of the perpetrator in the TV show, the whole thing was put together by the guy playing the dad, he wanted to be one of the main cast, he's white, ergo the kid is white too. It fits a pattern, but I suspect that race didn't really come into their thinking. If it did, then there might have been some recognitiuon that the point of this thing is 'it could happen to your kids', and they know that most Brits are still white and wouldn't really identify with that message if the show was about another angry negroid stabbing people.
This sort of stuff is where the civic nationalist in me comes out. My son is at an inner London school so there's a lot of browns, but the main distinction is class. There are kids with immigrant parents, but a lot of them are highly educated professionals with well-paying jobs who are pushy about standards and expect good schooling for their children. At the same time you have poor white kids with single mums who don't really give a shit about whether their children have a good education. Immigration is ok so long as the immigrants are upper-middle class secularists who speak perfect English, it's the dirt poor thirdies who cause all the problems.