That's sort of the point of rehabilitation, and the end of a prison sentence being the end of society's punishment. If you have a legitimate reason to find out

That's sort of the point of rehabilitation, and the end of a prison sentence being the end of society's punishment. If you have a legitimate reason to find out a criminal past you can request a criminal background check. And that's not even including all the other legitimate reasons, like any one who did something stupid as a teenager, has a vicious stalker, did something embarrassing once, has changed their views, has changed themselves, etc. People change. Computers can't comprehend that.