

You’re saying that it doesn’t matter because the US government is able to prove his citizenship, but that isn’t in question. The crux of this matter would be whether OP was ignorant of his citizenship and if that ignorance would have any relevance to his case.
Securing official documents only available to American citizens makes it more difficult to argue that he was ignorant of his status as an American citizen. He likely could still make a compelling argument (provided he acts quickly), but it does make it a bit more difficult.
Thomas Jefferson, 1787
I think this quote puts it aptly. It obviously comes from a more tumultuous time, but the United States was borne out of the idea that violence is a valid response to injustice. Law and order are preferable to anarchy, but that doesn’t mean that all law is valid. When the laws are used to insulate the powerful few against the many, what reason is there for the many to follow the law?
This often-cited quote from Jefferson urges regular rebellion against the law so that the powerful will never lose sight of how tenuous their position is. If you let the powerful manipulate the laws for their own benefit against the interests of the rest of society, you’ll be left with a population that has no interest in upholding the law.
That is ultimately why people are happy to let this man face no consequences. People are angry at the billionaires, especially those in the health insurance industry. And this action is being picked up as a warning shot across the bow. Society is saying that we are sick of the status quo, and if things keep going as they have been, this is not going to be an isolated event.