So Jewish law promotes committing fraud against the US government and says you should feel bad for the person when they get caught?
No and no.
Jewish law obviously does not promote committing fraud. Why do some in the Jewish community commit fraud, you ask? I believe it's because those Jews figured out a way to do it, whereas other potential tax-dodgers have not. If other people would figure out how to do it just as well, I can assure you that there would be the same crimes everywhere.
Credit card churning is a great example of this. Although it's not a crime, it goes without saying that if all credit card holders would know how to do it, they WOULD be doing it.
As for an individual getting caught, while Judaism does not
condone any crime, and in most cases even considers the crime to be a sin, it does not "unJew" him or her. They remain a Jew despite their crime, and as such, Jews ought to assist him in the ways the Torah commands one Jew to assist another.