Atheists: Is it immoral to get rid of criminal records after they served their time?

There's a benefit to keeping the records, as the information is necessary to comply with sentencing guidelines, which depend (in part) on past behavior. It's also valuable to law enforcement agencies to predict future crime, or make it easier to convict reoffenders, who often follow patterns of behavior that can be modeled with a surprising degree of accuracy.

But I think there's a good argument for making these records inaccessible to people outside the courts, and law enforcement agencies.

So murderers and rapist for example should be given a clean slate?

All decent, educated and intelligent people will pity you since if you can defend that idea you obviously have immoral character and are probably at danger of doing such things yourself!

That would depend on the crime and the prison system in place.

Is the crime petty theft or illegal drug use? Or is it murder?

Is the prison system harsh and punitive or rehabilitative?

Too many variables to give an easy yes or no answer.

Forgive, but never forget.

If the law allows you to clear out your record and this would be to your benefit then do so. It is called expungement.

It depends on the offence but in most jurisdictions there is a time limit on notification of a criminal record. The record is still there but it is not available to employers or others once five or ten years have passed since completion of the punishment. The time depends on the offence and the jurisdiction. Someone committing a few offences and going to gaol when they are 18 should not have it hanging over them for the rest of their lives if they don't reoffend.

Sometimes you have to be willing to accept some consequences of your actions are long-lasting. They do not always end when we want them to. Somethings are as permanent as suicide.