Once upon a time, when kids were bad in school, the school would punish them. I know teachers who had special paddles for these kids. Some of these paddles even had names, like Equalizer or Corrector, and even The Punisher. When these "bad" kids were intimately introduced to these paddles, a call would go out to their parents. When they got home, these kids would be in even more trouble. They'd get punished much more than what the school would put out.
Then, somewhere along the line, parents flipped on the system. Once their teary eyed little brats turned up the water works, the parents would threaten the school. Some parents sued. Some teachers got disciplined for disciplining the kids. Next thing you know, teachers were afraid to discipline the kids that needed it the most. The admin sides with the parents instead of the teachers. So now instead of the one or two "bad" kids per class, you have over half of them doing as they please knowing that nothing can be done to them. Could these kids be turned around? Sure, but someone has to care about them enough to punish them when they are bad. Not just give in because it's hard or they don't want to see their kid cry. The system starts at home. The schools can only do so much without support from the parents.

Bernd, great job taking in those kids and giving them another chance. The world's kids needs more people like you to help out.