Journalists sometimes talk about the public's "right to know". This directly contracts an individual's "right to privacy," so the journalist has to weigh balancing interests and make a decision. (If they screw up, the courts will review it, though the damage is done.)
Years later, it's not unreasonable for some other person to weigh these balancing interests again. Someone has to make the call balancing the public's "right to history" versus the individual's "right to be forgotten".
This can't be automated. You're not going to make a good decision without some person (journalist or historian) evaluating the particular case.
(By the way, I don't think talking about "rights" is at all that helpful when thinking about balancing conflicting interests.)