From here; there may be some mitigating circumstances pertaining to a resolution, but that doesn’t change the offense.
The USPS wanted to sponsor a clean racing team. They put it in all the riders’ contracts that they could not dope. Not only did they dope, but also (it is alleged) the team turned out to be a criminal doping conspiracy run by Armstrong so that he could win races and get rich.
The Federal Claims Act covers knowingly causing a false statement or record to be made in order to induce the government to pay a false claim – in this case, $30M worth of them. Technically, each of the riders is liable (for treble damages plus civil fines), but of course, Armstrong was the ringleader, and he wound up with all the money.
Additionally, any favorable publicity the USPS may have reaped at the time of the team’s wins has now been offset by all the negative publicity and abuse heaped on them at the worst possible time.
That’s the case. Armstrong has apparently offered to pay $5M to settle it. The DOJ believes it can recover a lot more for American taxpayers in court.
The sermonizing, philosophical conclusions are that bad things come back to haunt you, etc… Practically, you can see the logic behind “deny, deny, deny.”