I get that, if you want to be cheese-paring about it, what you say is in a narrowly technical sense correct. But the motivation here is identical to that which moved my first real boss to cover a $200 parking ticket I incurred through what I'm willing to admit, and stated to him at the time, was inexcusable carelessness on my part in failing to observe a sign. He nonetheless covered the fine, considering that, since I was in a position to make the mistake as a result of carrying out his business, it was reasonable for him to relieve me of the consequence. (Once - his exact words as I recall them were "now, you fuck it up again, you're on your own".)
That's the same kind of motivation I see in byuu's intent to make this situation right with the shipper, instead of blaming him and doing nothing. You can argue if you like that byuu shouldn't feel responsible. But I think we'd all enjoy a better world if more people more often did.