If someone has already done something horrible, it is likely that they will take advantage of you if you show a bit of compassion or mercy. Justice is more effective in getting the message across, and it provides closure to the victim, whether that is yourself or someone else. Justice also acts as a warning to others that might consider doing something unlawful or inhumane.
Mercy do not have a long term impact. Rather it creates an indiscipline environment. Mercy given is sometimes too quickly forgotten by the culprit . For any society to remain in peace and harmony it is a necessity to punish the wrong ones.
Victim should be considered first and foremost.
First of all there are some people who cant stand the thought of evil and would never hurt anyone or want to hurt anyone while there are people who cant help themselves and have to do evil and cant stop. I know what its like to be both. I was really bad from age 5 to 20 and then something changed and now my feelings and logic are much different. I couldnt do anything to prevent myself from doing evil. My feelings tortured me until i hurt someone or did whatever i was wanting to do. Im no longer religious and i dont believe in god and im a better person now than ive ever been. Dont believe in free will either. If i believed in free will id be saying yes. But like i said its easy for some to be good if not impossible for them to be bad while its hard for some to be good if not impossible for them to be good. We think people with addictions need help and addiction is the cause of a lot of evil. We are all pleasure addicts. Everyone is addicted to something. We dont choose our addictions and if we have free will we still dont choose whether or not we will be good or bad as circumstances determine that and thats been proven to me by my child hood and my adult hood. I know some people cant help themselves. People are sane or insane because of the physical condition of the brain. People are happy or miserable because of the condition of the brain. People are smart or dumb because of the physical condition of the brain. Could they not be good or bad because of the physical contrition of the brain? Look at kids that are abused sexually. They all do certain things like lighting fires and or torture animals and other stuff. There seems to be causes for our will that are beyond our control so id have to say that mercy should replace justice. It will sound crazy to you but there are ways this could work. And ill explain.