There is a federal law in play, too. I assume they are in America “to make a better lives for themselves,” as many are apt to say. But what happens if they aren’t here legally and eventually caught? Three squares a day? Tossed back to their third-world hellhole?
The letter carrier has injuries, maybe nagging injuries that will last awhile. The criminals will get slap on the wrist if caught, although it being a federal crime might make it a bit harder slap than usual.
Something similar happened to a friend of mine 10+ years ago. He has back pain to this day. The juveniles got community service. My friend was not a federal employee, but he was a school teacher on duty, so specific state laws came into effect. That didn't matter much.