Those are the types likely to be committing a lot of the crimes. Come to a working class town and see for yourself, or go on any local town Facebook group or council page and look at the comments.
I'm in Tottenham I don't need to go to your town to get the point. However the point remains, you can't just arrest an entire social cohort.
Indeed, that's why it's recommended to stand outside the school gates and arrest them as they leave school. Very efficient.