Hacker Khan
Yurt Dwelling, Yoghurt Knitter
IMO that is a somewhat romantic Blue Peter view of the attitudes of modern youth.
It may be true in the leafy suburbs where there is little real contact but that would be less of the case in many inner-city areas. Gangs are very rarely, if ever, multi-racial.
I would argue the opposite and that kids growing up in the inner city will have much more exposure to different cultures and races. Where as kids out in the leafy shires will have a lot less. And generally the more exposure you have to something the more you just accept it as being normal. And are more tolerant of it.