Because the lied to the government and misclassified the drug as a generic. By doing this, they can give out half the discount as with brand name drugs. Generics are discounted ~11% when sold to Medicaid, but brand name drugs are often discounted 20-30%.
Then just fine them, why does this have to be a criminal issue? It should only be a criminal issue when they did this knowingly and maliciously instead of checking the wrong box somewhere.
My economics professor had an ax to grind but he's right in that we don't live in a free market.
He gave the example of how the sheriff paid a gas station a visit when gas first reached a dollar. He said the gas station had two choices: sell at 99.9¢ or lower or shut down the gas station.
Actually the gas station was already selling at 99.9¢ because that pricing was already in effect from when one gas station owner sold it at 12.9¢ per gallon and everyone copied him since they were losing business.