Without police to protect the "young dude" he'll face consequences or potentially even be prevented depending on how well those "old people" know their neighbours.
I lived next to a 75 year old woman, if someone tried to rob her, even knowing that the police would arrest me and the courts would send me to prison.
They wouldn't make it back outside.
Their knees and elbows would be dislocated and they'd be laying on her kitchen floor screaming until another neighbour called the police to come and arrest me for defending her.
I'm pretty sure without the police more people would take responsibility for defending themselves and their neighbours.