Serious question... How do we know when someone's past actions are no longer relevant? Obviously if someone wrote a bunch of racist crap yesterday, they shouldn't be given a pass because they didn't write any today.

I agree there needs to be a path forward for people to move beyond their mistakes, but it's not clear to me that time since last known offense is the only qualifier.

You can evaluate people by their more recent actions. Of course, the more distanced you are from them the harder it is to evaluate them well. So it's a balance of evidence and risk.