Their is a long list, but I will tell you one of the main main reasons.
The Police/Criminal system in CityRP is completely forgeted up. Criminals are free to get various weapons and completely unload on everyone. Then when the police are required to stop them, they are forced to run after the criminal swinging a baton and attempting to dodge a clusterforget of bullets just to arrest them. Worst is, the police can't even fight back. If you're a cop and you shoot the criminal then you get demerits and become a criminal yourself.
Last time I checked self defense shouldn't make you a loving criminal.