I dunno, I guess maybe we'd just disagree on where the line is drawn. Murder? Rape? Something of that caliber? Nah, I'm not just gonna assume or trust that the person has changed, even if it'd been 20 years or whatever.

Bank robbery? Well, I dunno. Armed robbery? Did anyone get hurt? Maybe that's not ok, no matter how much time has passed.

But yeah... drugs, whatever. Super petty crimes where there wasn't any violence or physical threats involved? Yeah, maybe no big deal if enough time has passed with the person leaving that kind of life behind.

But even then, it's hard to say. In this article, it seems like the faker didn't do anything that bad before stealing this other guy's identity. Like, the kind of stuff where, 20 years later, we'd probably just shrug and be like "yeah that guy's got some stories". But he ruined another man's life, causing a situation that led him to become committed to a mental hospital merely for claiming that someone else had stolen his identity. (Sure, the judge in the case almost certainly acted improperly, but that's not really the point.) I don't think that's something you just sweep under the rug, even in another 20 years.