You know, absolutely everything you wrote is spot on, zeroed right on the mark correct, as far as I'm concerned. Absolutely explains "why they'd want to shame them". Truly, you translated human nature into the comment very well.

But...human nature is...well.

All that you wrote is what someone who is looking to make someone face and own their decisions and the consequences of their actions should do. But the reason why the poster you commented on is correct, is because the shopkeeper in the comic, by their own signage, isn't someone who is looking to merely chastise to engender better behavior.

The other half, is actually dealing with those consequences. As you noted, the person who chose poorly has invited their consequences upon another living being, whether through willful action or unfortunate circumstance, doesn't matter.

The person will need to learn, but the living being who is not the person, is actively enduring those consequences. The reason why they let you drop off babies at fire fighter stations without making you have to go in and sign a form, is because unrestricted absolution leads to more babies being saved.

When a person has an out, out of a problematic situation that they can utilize without furthering worsening their situation, they will take it. Note that I said without worsening, the sting of the original problem always remains as hook enough for self improvement. A person will have to eventually step up to fix themselves or they should be stopped, and discouraged, yes.

But if someone else is choosing to instead, rescue or protect or rehabilitate the collateral victims of the consequences of another's actions, the most effective course is to focus solely on that which they seek to save, as the person who did the damage is not their responsibility and engaging poorly there, would result in less saving of that which they would protect.