Remind Me Again Why These Banks Are Our Friends

Standard Chartered Bank in the U.K. is accused of intentionally hiding transactions involving Iran in contravention of international sanctions to the tune of 250 Billions Dollars.  Do international bankers and their über rich clients live by different rules than the rest of us?
When warned by a U.S. colleague, a U.K. based colleague’s response was, “”You f—ing Americans. Who are you to tell us, the rest of the world, that we are not going to deal with Iranians.”  Hmm.  Do I detect a little hostility here?  The sanctions were agreed to internationally, not just mandated by America.