In addition to depriving a person of liberty, slavery involves total obedience to demands. And, while we have formally terminated slavery as a legal status, the demand for submission remains manifest in the culture of obedience. Culture is the result of coercion. So, the culture of obedience is inherently abusive. Abuse persists as a cultural norm, transmitted from generation to generation by perp and victim alternatively. It would probably not be wrong to identify abuse as a “kinder and gentler” remnant of slavery. And that is why, unless we formally exempt some particular victims (child, elder, animal), abuse is legal. Oh, we may call it “discipline” or “compliance” or even “obedience” (a virtue by tradition), but the bottom line is that using people and abusing people is lawful and, indeed, our agents of law enforcement are rewarded with an exemption from all negative consequences of their actions, if their actions are consistent with the rules (qualified immunity).
Issue a blanket pardon and what do you get? Abuse and, in individuals with a moral sense, a cadre of people bound by a shared sense of guilt. For guilt is like those spots of blood Lady Macbeth cannot get rid of.
Absolution may remove the punishment; the guilt just gets shared and spread around. That is how we ended up with hundreds, if not thousands, of priests ensnared in a web of shared guilt where the subservience to superiors was secured by crimes against children.