|This page in a nutshell: Do not criticize a repentant editor in good standing for past misdeeds that have stopped reoccurring. This is a failure to assume good faith and instead is a personal attack.|
But the Talmudic villages were, in fact, far more humane and forgiving than our brutal global village, where much of the content on the Internet would meet the Talmudic definition of gossip: although the Talmudic sages believed that God reads our thoughts and records them in the book of life, they also believed that God erases the book for those who atone for their sins by asking forgiveness of those they have wronged.
In the Talmud, people have an obligation not to remind others of their past misdeeds, on the assumption they may have atoned and grown spiritually from their mistakes. “If a man was a repentant [sinner],” the Talmud says, “one must not say to him, ‘Remember your former deeds.’ ”Unlike God, however, the digital cloud rarely wipes our slates clean, and the keepers of the cloud today are sometimes less forgiving than their all-powerful divine predecessor.
Wikipedia is a community with an infinitely long memory. Every word you have ever said on Wikipedia can be measured in bytes, and will be saved on a hard drive on some server. No one has a perfect record. Everyone has some misdeed or mistake in the past. That's how people learn. If someone makes a mistake and corrects it, you should once again assume good faith. It does not matter how big the past mistake or the disruption was. What matters is how the editor has learned from it and grown from it.
Wikipedia blocking policy states that punishments are preventative, not punitive. If the editor is no longer violating any policy, it is against Wikipedia policy to keep reminding them of past misdeeds to malign their current actions. It is an accusation of bad faith, is a personal attack, and an example of incivility.
If you believe the editor is continuing their disruptive behavior, start a new discussion instead of bringing it into a current dispute.
Editors sometimes continue their disruptive behavior, or game the sanctions or warnings from administrators by inventing new disruptive behaviors. The appropriate channel for that is the administrator noticeboard, or other methods of dispute resolution. Use those channels if you believe they are continuing to be disruptive. Otherwise, do not bring their past misdeeds into a dispute, especially when that dispute is about another editor's ongoing misdeeds.
One special case of pulling up past misdeeds is if an editor is requesting administrator rights on Wikipedia, or somebody else thinks they should have them. Because admin tools require a great deal of trust and responsibility, and even an accidental and good faith misuse of the tools is problematic, it is reasonable to look over past misdeeds to help determine if the editor has an understanding of policies and guidelines. However, this only goes so far. There's probably no value in deciding an editor shouldn't get the mop because they had an edit war 7 years ago when their account was four days old.