CAN BYGONES BE BYGONES?

I've heard many times people saying let bygones be bygones, but I keep asking, how will you let it be bygone?

Humans have what we call memory and as time passes by, we remember every bit of information, hurts, experience, sad moments and happy moments.
We can't just let it be bygone, no matter how we try, we must remember everything, how we felt and what we wished happen that period.

You can't hurt me and come tell me to let bygones be bygones, how? I may forgive you, but I can't forget the fact that you hurt me.
Now! Tell my why some act are punishable in the court of law. Is it not to let the person know that what he or she committed is bad?

I don't blame those who keep pursuing a case for years when they get stabbed to ensure that the doer taste how the pains feels like.

I am not saying that we should pay evil with evil, revenging the same kind of hurt, but we shouldn't let some things be bygones no matter how long it took to know the evil one has committed and let them pay for it. It doesn't mean that you are heartless, is to let them know the gravity of what they did to you as such, they won't ever have the thought of repeating anything bad.

I see a lot of cases been over looked e.g rape cases, killing, fraud and theft from the minorities to the high class. And nothing is been done to that regards. The only thing the victims of the circumstances get is condolence messages and visits, nothing is been done to bring the perpetrators to book. The pains of those affected is overlooked and that show that they are indirectly telling them to let bygones be bygones. How do you let it be bygone?

Bygone can never be bygone as far as I'm concerned,if nothing is being done to make those who partake in evil feel the pains the put other into after carrying out their evil, then it should not be bygone.