I can understand (intellectually, if not emotionally) why people end up as bailiffs and coppers and screws.
i dont think the analogy is fair at all, firstly we've established that most of the people defined as lumpen come from the very poorest backgrounds, the economic underclass if not the moral one - this is far from true of coppers and much less true of bailiffs and screws
but more importantly the people you are talking about are children, there is a big difference between the organised and ongoing class treachery of the filth and a kid who joins a gang cos he's scared of being bullied or gets carried away and does something stupid in the heat of the moment