Are the Police Courts and CPS on the side of the law abiding or the criminal?

time and time again we hear that the police "can do nothing" when thee is a complaint of behaviour and the harment of residents particularly the elderly. Then having been provoked and insulted beyond tolerance they do something for themselves only to find that they not the perpetrator who is arrested and humiliated having to answer for THEIR conduct towards the miscreant. It seems that there is something rotten in the system