Well, don't ever assume lack of sloppiness. ;) But to the large question: markets are built on trust, and the SEC has the job of ensuring the trust bedrock of the US markets via enforcement. A high-profile move like the one we're describing here, manipulating the US markets so brazenly, is worth spending more money than exchanged hands in the fraud to find the perpetrators, just so they can put heads on pikes and make everyone feel better that the system works (because the net loss of value if market trust breaks down is much, much higher).