I think I read something to the effect that your personality and maybe your moral compass (not the word they used, but I can’t recall how they put it now) was fixed by age 5. But, I wonder if using some sort of behavior modification you could at least teach them to behave in an acceptable manner? I don’t know, grasping at straws.
The thugs on the street don’t fear punishment. They know the legal system is toothless, and even if they have to “sit down for a little minute”, it’s an inconvenience, just punishment, which they soon realize is an opportunity to refine skills, gain more legal knowledge, get fit, and network contacts to further their criminal enterprise.
They also don’t fear law abiding citizens with firearms. They will avoid the ones that know of and who are wise to their tactics, but in a pinch they will just shoot first rather than give an armed citizen a chance to comply with their demands.
On the street, being decent, respectful, and genteel equates to being soft.