From TFA: "It is a cautionary tale of how European banks, spotting a lucrative business opportunity that American rivals shunned, opened their doors to countries under sanctions and ultimately exposed their reputations to the stain of criminal cases."
How do we know that American banks shunned it? They too could have been disguising transactions and hiding illegality. It's not like US banks are known for avoiding 'lucrative business opportunities' that aren't entirely legal. Perhaps the whistleblowers required haven't come forward, or perhaps the investigators just haven't looked too hard...
