are to protect everyone.We have Jails to protect criminals,if we leave them in the hand of public,it makes it worse.Just like in third world countries,if people caught a thief red-handed,you could not imagine what happens to him next,a mob will beat him till he collapses.
If everyone is like you, then we hardly need any laws, but sadly, all human beings are not same. Some people are like snake, it will not benefit them anything but they will poison others.
There are people who will forgive even if their family was killed, there are people who will come to fight even if you say something about their sister or mother or someone they love.